I’ve always viewed decentralization as a kind of fractal — there will always be some form of concentration or “clumping” if you will, at some level, as you zoom in or out.
In that sense, decentralization is very close conceptually to oft-misunderstood concepts like “freedom” (of speech, for instance): it is highly specific to a context (specifically from government), and there is always a bound. It is never totally “free” in the way most people understand it (it doesn’t protect me from getting fired if I say fuck you to my boss).
Decentralization is the same way: in the end it is a design choice, targeting specific levels, with specific objectives in mind. Total decentralization is a concept that needs to be dropped from our lexicon or calibrated heavily in context of exactly where and to what.