While it's easy to look askance on this flavour of rhetoric in a modern context, the explicit way it was supposed to work is that legions were supposed to be retiring to the land they were given when they retired, and that way the lands that Rome expanded into were supposed to be quickly and fairly densely filled with retired legionaries working the land, speaking Latin, growing enough crops to be self-sufficient in a crisis, paying taxes, having little baby future legionaries, and being available to form the core of a militia if it came under attack or if the locals decided they didn't like being part of Rome any more. When it actually works this way, this removes all the usual weaknesses of freshly-conquered provinces and makes for a very durable sort of nation that has a lot of leeway to ride out all sorts of crises.
But what it doesn't do is rapidly enrich the people that are already rich, and we all know how much of a problem that is.
So you buy the land off the legionaries - or, better yet, just reform the entire process to seize the land for yourself and have retiring legionaries given the market value* of a plot of land instead - and form all of those small blocks of land into massive cash crop plantations worked by slaves. You maximize the economic output of that land, having it creating larger amounts of more valuable crops than if it was all still individual farmsteads, and the state doesn't even benefit from this because there were various aristocratic privileges and plutocratic tricks you could use to dodge your tax burden. But while those slaves are working the land, they're often not speaking Latin, they're not growing staple crops that could feed the province in a crisis, they're not paying taxes, they're not having little baby future legionaries, and they're certainly not forming the core of any militias. In fact, they have a lot of reason to throw their lot in with those who don't want to be part of Rome any more.
Told correctly, every single scrap of blame for this should be levelled at the patricians, and the dynamic at play is one that should resonate with a different set of modern concerns.
* lol