Gamewise, high tib rolls suck.
Narratively?

Canon GDI got screwed by tiberium going at about 'average' then mutating. So they wereeventually, had lost entire blue zones. And lost the war so badly to tiberium that even after the TCN had been built vast swathes of the landscape, reclaimed from the crystal was left as barren desert and wasteland.
In this game, the players, wanting to avoid that, and in an effort to fix the economy went all in on tiberium abatement and mining. And, we're actually, even despite high rolls, ahead of where canon GDI was tiberium wise.
At the cost however, of not focusing as much on other things such as military. It *is* a tradeoff, as it should be.
Canon GDI kept up the pressure, and post war invested heavily into their military and bluezones.
Right now, we're still, and have been dealing with insurgents and low level nod strikes for years. Canon GDI going full military wiped out as much of that chaff and mid level warlords as they possibly could. Thinking they'd deal with tiberium afterwards. Which led to Nods highest tiers and elites all going into hiding, with the singular exception of Kane waking up the Marked. Laser concentrating everything on the tacitus labs and stealing that. Then going into hiding again. Up until GDI was so badly weakened by tiberium that they had to accept Kanes knowledge of the TCN.
Now, we're doing better against tiberium currently, but we're definitely behind on the military currently. Which nod has taken advantage of, perhaps overplaying their hand even, since we're now focusing on our military to keep up in that respect, and thanks to our greater economy than canon GDI, we (hopefully) will be able to catch up there.
All that said... Lorewise this is pretty fitting GDI has always struggled to balance Containing tiberium with fighting the brotherhood.
Tiberium dawn, tib arrives and nod starts a war. GDI starts fighting a war with Nod as they expand from a corporation into conquering nations and expanding their power. GDI beats nod. But in the years after the war, GDI isn't quite yet the world government, at least not enough of it. So tiberium keeps spreading, helped by some either trying to spread and mine it for cash, or for idealogical reasons. Tiberium mutates, and screws with the oceans. And then the Nod warlords that GDI has kept a lid on and controls through keeping fractured and playing warlords against each other, while GDI struggles to deal with the whole world falling apart. Then Kane returns and a whole second tib war starts.
then after that CABAL awakens.
But fine, GDI handles the Cabal crisis with Nod, even sponsors some leaders like Marcion they can control, and in the meantime goes through a massive effort to fix the oceans tiberium algae problem, mostly containing it. There's a couple of setbacks with mysterious tiberium explosions. The rio insurrection and some Nod warlords ruling their own little corners of the world. But it's
fine. Kane is definitely dead this time. Meanwhile, tiberium has spread throughout the world, various countries have lost huge sections of their landmass to the crystal or had their government collapse entirely. And so in all of
that chaos GDI steps in and reforms itself to fill the role of world government, with the total dissolution of the last of the old world nation states. And yeah... Transitioning to the Zone model. And focusing on the blue zones, keeping them safe, and using them as a beachhead to protect valuable industry and push back against tiberium from the safe zones. Well, that is the logical play. Unfortunately Nod use that to attract the disenfranchised. But, you know what? The blue zone Idea
works. GDI is able to keep them safe, and push back against the crystal, even cleaning up enough to not only expand blue zones, but create entirely new ones such as reclaiming Munich.
GDI's abatement strategy was working. And nod had been mostly cleared out, relegated largely to a handful on fortified yellow zones, or hiding in red zones. Small in numbers, judged little threat with few/no attacks. So much so that GDI is shifting its budget from military to the abatement, closing down military bases all over the world.
Then Bam. GDI's ion cannon network is downed. Suddenly Nod is attacking everywhere. Kane is
back again. After your best commander killed him face to face. Now Nod's attacking blue zones all around the world on all fronts. They shoot up tiberium silo's and refinery's wrecking blue zones and causing all kinds of conventional damage too, destroying buildings and infrastructure and killing people. But fine. GDI goes to work. They push back Nod. Ion cannon the temple once again. And holy shit Europe just got covered in tib.
Abatement is set back years, if not decades. Entire lifetimes of work gone. Millions dead. GDI is left trying to pick up the pieces, bracing themselves for lengthy reconstruction and hunting down the Nod remnants. But nope. Aliens.
Aliens invade, and because Nod is doing Nod things and hiding out in yellow/red zones in their secret bases the Aliens are focused on the biggest population and industrial centres, nearly all of which happen to be blue zones. But you fight, and lucky for GDI some sane Nod troops join to save the world from the alien invasion.
An alliance which lasts until Kane returns from the dead again and announces it with another goddam nuke.
Then. Tib war three ends. And you've got the hard task of winning the peace. The world is more filled with tiberium than ever, so that's where the tib scientist head of the treasury focuses his efforts. And it's working. You're measurably slowing tiberiums spread, and even pushing it back in places. The military is asking for shit and the civilian populace aren't particularly enthused, but an industrial collapse is averted and you're getting on top of things.... then Nod goes and kills a mining crew. So fine, GDI invests more in military.
And that's where we are now. GDI has
always had to juggle dealing with Nod and tiberium. Often in between dealing with civilian governments/treasury who tries to balance the budget. but those problems with governance don't go away when GDI becomes the government, indeed, now they're not just an army, but are in charge of everything. So juggling nod, and tiberium, and mundane day to day..... And GDI actually manages it for the most part. But then wacky shit blindsides them.
Kane returns from the dead. Tiberium mutates. Nod gears up for and fights a massive war. You fight them. Nod goes quiet. Unexplained Tiberium disaster. Nod gets stomped and goes quiet. Focus abatement. Nod recovers and alpha strikes. Kanes back again. More tiberium disasters.... A goddam alien invasion... Kane returns from the dead. And here we are, getting things under control, gearing up to stomp nod into shutting up and leaving us alone after they've just slapped us around the head again and killed our miners. And... not too far in the future we're looking at Tiberium mutation.
That's.... just all kinds of 'bruh'. Any one thing GDI can easily handle. Nod or Tiberium. They can even, just about keep on top of both most of the time. But then every now and again something new comes around to give GDI a kicking. Cyborg armies, or aliens. And every time you think Nod has been beaten into the bedrock Some hotshot general fucks things up for GDI and/or Kane returns from the dead and the brotherhood goes on a rampage. Or just when you're getting a handle on Tiberium it goes and mutates. or critical research labs are sabotaged leading the loss of months or years of classified research data.
This has been a long ramble but two things. 1 GDI is doing okay to handle all this. Both in the canon timeline and here. And 2 It's entirely in keeping with command and conquer for tiberium rolls to be sucky and everything to keep going wrong but GDI limps on anyway.