At least I don’t…
I have my own domain, and of course I use it with my email provider. But the problem is, I don’t use that domain for anything other than emailing others. I don’t use it for signing up for various online services.
Instead, I use the generic email domain. The reason? I just don’t want to be personally identified. I don’t want every account to be associated with my online identity (my website).
And so, if I lose access to my email provider, all of my accounts are gone. Very troublesome, indeed.
And, I suppose, a lot of people do the same thing. A lot of email providers advertise “masked emails” where they generate an address for you, to use for your online accounts. But that permanently ties you to them. Does nothing for portability. You lose access to your email provider, you’re out of luck.
What are the alternatives? Well, maybe we could try implementing another method of authentication that doesn’t suck? And the other, more realistic approach, well, I guess you could just buy cheap domains to use instead. But there’s no truly portable way to authenticate yourself with email — you could even lose access to your domain.