> No they wouldn't. Because they would face both their internal rivals and external rivals most importantly the empire itself.

And under the empire they'ed be competing with those same rivals to be the ones that the empire keeps in charge.

> There was not as much civil war as you think and not in most regions even if there was.

The crisis of the third century had 26 people claim the title of emperor in 50 years. Wikipedia lists 111 civil wars and revolts between 30 BC and 476 AD with the longest period between civil conflict being the 26 years between the revolt of Saturnius and the Kitos war. From the year 227 to 324, there wasn't a single period of peace lasting 5 years.

It doesn't matter if it's happening elsewhere in the empire, the fact is a large portion of the Roman military is doing something other than defending the empire.

> Very questionable. Quality of life has little do with it. People for the most part didn't have much say in it, rather the elites.

If the people are unhappy, new elites rise to power by leading people in overthrowing the old ones. Yes, there wasn't a democratic process by which the local populace could simply choose to leave the empire, but the populace did need to be placated. Who do you think the "bread and circuses" were for?

The empire was just as capable of granting titles and monopolies in the fifth century as in the first, that clearly wasn't enough to keep the provinces in line.

> Maybe your point is true for the late imperial period around the med, but its certainty not generally true.

We are talking about a change in behaviour in the late imperial period that caused the fall of the roman empire.

> Yes, but what matters is the integration not the infrastructure.

I'm arguing they are one in the same. A strong and cohesive society builds and maintains valuable infrastructure like aqueducts and roads that improve quality of life and thus make people want to integrate with it. A weak and divided society stops building and maintaining this infrastructure which causes quality of life to stagnate or decline which in turn makes people less invested in preserving a unified empire.

> Much of the infrastructure had already been having issues since the 3rd century.

You don't see any correlation between the crisis of the third century and the onset of infrastructure issues? Rome did not suddenly collapse, it was a gradual decline over the course of centuries, which correlates very well with the slow but steady decline of its infrastructure.

> The elites with actual power (not just money) were no longer centralized or unified. If you actually look at trade pattern and urbanization they don't actually decline until much later. For the most part the Fall of the formal empire is a non-event.

> The collapse of the Roman Med economy and the de-urbanization of Italy mostly happens later.

Yeah, and the aqueducts didn't poof out of existence in 476 AD. But the question is why were the elites with actual power decentralized? Why were they no longer unified? You're right, the population was still there, the money was still there, so why not the power? Clearly something had changed.

Now I'm the first to admit that blaming the fall of Rome solely on a lack of infrastructure spending would be absurd. There were many changes over the centuries which contributed in a myriad of ways. But the fact is in that time period the ability to quickly move armies via roads, the ability to produce massive quantities of food via irrigation, and the ability to house large populations in cities via plumbing were major selling points for the empire. People were proud to be Roman, people would spend years in service to become Roman, people would willingly die for Rome, because in their minds this was the beacon of civilization and their children would live better lives as Romans. Eventually, people no longer thought that way. The barbarians which started ravaging the empire and setting up independent kingdoms from the fourth century onward were not particularly numerous - any particular group was only a few thousand people, and there were never more than 1 million total, compared to the empire's population of 40 million, but the provinces put up little resistance and shifted their cultures to match the invaders. The end of euergetism and the decline or roman infrastructure was likely both a cause and consequence of this ideological shift.