Until you're required to use their software for, say, banking or legal procedures. You DO NOT want this to become the status quo

Indeed, IDK if you remember back in the bad old days but you used to need a specific browser, and if that browser was IE, good luck if you weren't on Windows. Sites would just block you.

I really hope this doesn't become a thing again - it's already stupid with so many "best on chrome" stuff, but at least I think Apple and Safari put a dent in that because Apple users are a big enough group, and generally identified to have and spend more money than Android / Linux / Windows users so there's that. And Firefox is... well... something. 10% now? IDK, it's hard to be single browser now adays, but with these "for security" things? Who knows.

I guess if Apple, Microsoft and Mozilla all refuse to go this way, it'll break it. The other option is something like Lets Encrypt being big enough they can't delist the attester, but it just attest everything so turns into garbage. Or enough accepted attesters (if it's like SSL PKI) "attest" that you paid them $50 that year and that's about it, so again, everyone who cares gets a Comodo attestation or whatever and use a browser / extension / proxy / OS / whatever that just sends valid garbage or spoofed stuff to them, like many do for the various existing non-secure identity fields.