I mean, the local Monarchs might be a lot more willing to do that if the Abiden had enforced the same rule/levelcap on the rampaging kaiju.
And/or done something about the fact that a given empire having it's Monarch ascend without a well trained replacement is probably not going to have a great time.
...yeah;
could probably also put a ounce more effort into improving the "stability" of the arena they have going atm.
like, I'd be surprised if there *wasn't* almost-continuous backstabbing surrounding (or even in) the arena that's ending alot of otherwise high-potential individuals.
somebody getting backstabbed doesn't result in a stronger fighter standing over their corpse; just a pure loss in total potential (by anime logic itself even--you have to fight someone in *some* kind of fair and square sense to get the narrative-driven boost).
edit: scratch that; I just remembered the start of
this arc has the protagonist's faction's lessor groups ambushed and killed in what was probably NOT a straight fight with similar-power-leveled people.
like, I get the lessor cults are not going to win in all likelyhood and probably won't ever have anyone get close to assend. but surely they act as a good foe for the others to grow by training/fighting with/against (and help them by allowing them to focus more on training and less on protecting villages and what-not) and every now and then, they produce an artist who actually has a decent shot (see a certain someone on the protag's team actually)--and thats assuming the "primary" cult's heir doesn't die which would mean the secondaries would be the ones to take over and ensure things ensure things don't just instantly collapse (so theres your point about the replacement thing).
to add onto the point and extend it.
It would also make the more sane monarchs (the one's Abiden probably cares about more about anyway, or SHOULD anyway) more inclined to like/trust them too as it would also let the whole deal not feel rigged from the start too since it would show abiden actually cares about the details (and the people) rather then just the outcomes of all this.
basically, this mess and this guy's attitude is the proof that abidan doesn't actually care about all the "little" people they claim to do all these horrably machivilian things to protect...just their power structure and their philiosophy of protecting the Way and those within it (which makes it a hypocritical lie).