The state of California has a higher population than Canada...there's very little reason that California shouldn't be able to almost entirely self-govern. At the same time, there's very little reason to assume a policy that makes sense in California and will likely be popular with the people there...will make sense in other parts of the country.
Yet we constantly see people unwilling to simply settle for state level policy wins and instead feel the need to force policy nationally. We don't need that any more than we need politicians from South Carolina trying to force national policy that will affect California.
We'd all be a heck of a lot happier if we could stop at the level of just talking about how backwards we all think each other to be rather than constantly fighting to keep the backwardness away.
I suspect more centralization could help with accountability ironically but there are other issue there including harmonizing different needs and values by region and deciding "who is right".
The three things to optimize and balance are "sensitive to local demands" (treating water by conservation needs in the desert or by great lakes or demands of road salt by road area regardless of climate would be a terrible idea), "ability to scale and administrate effectively" and "respectful of rights" - and all three may clash or agree.
So we are subject to strange rules about parking, shooting, building, water and power that make little sense in our small community.
But with 450M people in the US for instance, and wages and work the way it is, admit that the vast majority of people don't live in some village or small town. They live in metropolitan cities. With about the same hope of affecting their 'local' govt as the federal one.
And who has time in their life to go politicking at city hall? Average folks barely have room in their lives to go get an official ID so they can vote at their polling place.
This is a middle-class argument that doesn't apply to most citizens in most places.