Problem is, once you centralize, that remains in place for a long time, but the original intent, even if it was genuine, rarely outlives the people who implemented it for long.
Generally speaking, every point of centralization is also a point where a lot of power can be acquired with relatively little resources. So regardless of intent, it attracts people who are into power, and over time, they take over. The original intent often remains symbolically and in the rhetoric used, but when you look beyond that into the actual policies, they are increasingly divorced from what is actually claimed.
> Generally speaking, every point of centralization is also a point where a lot of power can be acquired with relatively little resources
This is why (1) shared principles and (2) credible democracy is important, to allow evolution of the centralized power (i.e. government) towards the shared principles, and why its corporate-bribed facsimile or oligarchic authoritarianism don't work.
Credibility of democracy breaks down as you scale upward (which you have to do if you want to centralize). Any representative democracy in which the representative doesn't know all the people they represent is already suspect, but when you get to the point where a single guy supposedly represents hundreds of thousands or even millions, it's kinda obvious that there's no meaningful representation involved. The only way to avoid that is to grow the parliament instead to the point where it ceases to function as a deliberative assembly (and then what's the point of it?).
Or you can have a bunch of smaller assemblies that actually are representative, and then a larger one to which assemblies delegate their own to cooperate. But that's exactly political decentralization - a multi-level federation.
Generally speaking, every point of centralization is also a point where a lot of power can be acquired with relatively little resources. So regardless of intent, it attracts people who are into power, and over time, they take over. The original intent often remains symbolically and in the rhetoric used, but when you look beyond that into the actual policies, they are increasingly divorced from what is actually claimed.