I bought the game at the of alpha with an email I lost access to at some point. I remember my Password and Username but forgot the email address I used. I think it also wasn’t even possible to change the email address in the Mojang Account back then. So I definitely didn’t sit around and ignored the migration, I even tried contacting the support.
Anyways what sucks is that I remembered my email address this winter, but already after the cut off point. Would have been nice to get to keep that very old account. But as others have mentioned, the experience is probably better with a pirated version anyway.