Right, but I want to validate my identity for cases where it is important to me. I also want to prevent others from assuming my identity in cases where it doesn't really matter (until it does). My identity here is not the same identity use on Reddit. At the same time being erroneously linked to someone else's posts on Reddit because they use this username could be a real problem. At he same time, I don't necessarily want my posts here to be linked to posts at Reddit or X or wherever. Rinse and repeat across thousands of web sites.
It's a problem with no easy solutions. In part, because no two users want exactly the same solution.
In Norway we have multiple national id providers. The banks have one called BankID which is what I mostly use, but there are other alternatives. These can be used somewhat interchangeably across different applications like my online bank, tax website, healthcare website, investment platforms, pretty much everything. I can also use it to sign contracts.
For example, I always use email login, never a phone number or Github or Facebag, and I barely have a presence on Google's panopticon, so never with my Google account. If a site demands it I just don't use it.
I also pay Fastmail to host my domain email, so that really helped get off Google. Yeah I gotta remember to renew every 10 years or whatever, plus $15/yr for fastmail; but what's the other option, I learn some SMTP package? No thanks.
It's a problem with no easy solutions. In part, because no two users want exactly the same solution.