None of the options you mentioned force sites to spend money maintaining a second version of their site, so they're all better than AMP.

I also think you have an exotic definition centralization.

> sites

Sites is plural, so this is not a centralized solution. There are multiple competing options.

> just stop indexing or boosting the garbage sites forcing them to change, that's what amp does yet again.

No it doesn't. AMP is faster, so AMP sites get boosted based on being faster. It's an indirect effect, at least according to Google. Google could have stopped at applying a big penalty to dog slow sites. No lock-in promoting tech required.

There was a huge missed opportunity for Firefox here to do some aggressive garbage removal in these sorts of pages. They'd probably have a much bigger share now if they had