A lot of those hoops are an important security measure though. Imagine if someone else could quickly and easily delete your account if they managed to steal your password.

No, a lot of hoops are barely even legal.

Many services don't even allow you to delete your account, just to disable it and have it hang around in their database as long as they want. That's a blatant violation of privacy.

no, most of the hoops are a dark pattern to discourage you not to delete and/or trick you into incomplete deletion.

presumably a .delete domain wouldn't be "quick and easy", you'd still have to authenticate and perhaps verify intent via OOB method. however, the link to the action would be well known and obvious, instead of having to dig dig dig around a website.