I like OpenID but I don’t get many chances to use it.
Large tech sites mostly allow a sign-in by OpenID, some board systems added that... well.
I don't know if you meant most, or that their implementation is shoddy. If you meant the latter, well, on that I'd agree.
I ran my own bare openID provider endpoint on my own domain for years... and as time went on, more and more of them deviated from the bare specs to shoehorn the larger openID providers' requirements in.