The only thing a POW change will achieve is a temporary reset to a level playing field.
That's right, but with how well known Bitcoin is known now compared to 2009, a temporary period of decentralised mining will exist.
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.
To paraphrase:
"The tree of decentralised cryptocurrency must occasionally be watered with the blood of ASIC mining tyrants"