Created my account in January 2010, used it for a lot of stuff.
Single sign-on turns into single point of failure... again.
I'm sure as hell not going to use Google, Microsoft, Yahoo, LinkedIn, Facebook or whomever for single sign on. I have enough trouble trying to prevent people from sucking me into Google+ and keeping my Youtube account separate from my Gmail account. LinkedIn and Facebook already want to get into my email to "build my social network" further. None of these are trustworthy companies.
I guess I'm going to have to add a dozen more passwords to my password database.
You're exactly right. When OpenID was getting started, I was quite hopeful that it would prevent lock-in and walled gardens. I used my myOpenID account. I also experimented with Google and Yahoo as providers. I was dismayed that while a number of small web sites were and are OpenID consumers, none of the big ones have allowed that. Eventually, I realized that's simply because it's not in the interest of a company with a large number of users to allow people to use outside accounts to log in. They know they can increase their power by restricting how users interact.
I was similarly dismayed when Facebook implemented an XMPP (Jabber) service but didn't federate, defeating the primary strength of the Jabber system. I was happy for many years that at least Google was interested in interoperability, but they've now shown they're little different from Facebook, Microsoft, Twitter and all the other behemoths in that regard.