That's right, but with how well known Bitcoin is known now compared to 2009, a temporary period of decentralised mining will exist.
Early bitcoin usage was a small user base oligarchy.
Could that last long enough before 3D printing of ASIC chips is possible? Maybe not, but I doubt it would take one more PoW change until we got to that point, and then the game changes completely.
Difficulty will increase, and people will still point their miners at mining pools.
To paraphrase:
"The tree of decentralised cryptocurrency must occasionally be watered with the blood of ASIC mining tyrants"
Perhaps you should consider another proof-of-whatever consensus, as spilling the blood of block builders who confirm your transactions in the ledger because you can't force an unwanted software change on them is like cutting your nose off to spite your face. Or perhaps consider making changes to the software design that they are happy to accept. One mans tyrant is another mans protector of freedom.