True decentralization is free market competition and the enemy of free market competition is barriers to entry. Proof of work is a barrier to entry.
Proof of work is like slicing meat for a sandwich.
Sandwich is like free market.
I want my meat to be sliced in the same thin sizes.
No competition whatsoever.
I want choices of meat and vegetables.
I do not want competition in my sandwich.
I want competition between sandwiches.
You broke the metaphor and now you have to fix it.
Economies of scale (EOS) is a barrier to entry... proof of work always benefits from EOS
Once EOS results in centralization (pools + asic) no one else can safely create POW chains without approval of the industry POW giants.
POW is like having someone producing sliced meat for sandwiches...
EOS + POW means the producer of the cheapest sliced meat owns the production of sandwiches because they can undercut all competitors prices...
If you assume that market participants only buy sandwiches with the most slices then no competitor can produce sandwiches with unapproved vegies or meat.