So for example, Firefox since version 119. Or Chrome since 117

Now, for most services ECH doesn't have an encrypted target server. But the important choice in ECH was in this case it just fills that space with noise. An encrypted message also looks like noise. So you can block all the noise, in case it's secrets, or you can let through all the noise (some of which might be secrets) or I suppose you can choose randomly, but you can't do what such regimes want, which is to only forbid secrets, that's not a thing.

We've been here before. When sites starting going to TLS 1.3 lots of HN people said oh, China will just block that, easy. But the choice wasn't "Use TLS 1.3 or keep doing whatever China is happy with instead" the choice was "Use TLS 1.3 or don't connect" and turns out for a lot of the Web China wasn't OK with "don't connect" as their choice, so TLS 1.3 is deployed anyway.

I doubt the Chinese government would care about that. They don't depend on the west for their online services any more than we depend on them. All that would happen is that the internet would bifurcate to an even greater degree than it already has.

It's extremely helpful at home in the west as a countermeasure against data monetization and dragnet surveillance. It certainly isn't perfect but at least it reduces the ability of ISPs to collect data on end users as well as forcing the government to formally move against the cloud providers if they want the data. Not that I want the cloud providers having my data to begin with but that's a different rant.