It is common for corporate email security appliances as well. URLs should not be used for authentication neither should email. I really want to pick brains of people that work on these types of systems to see why they don't think so.
Also, mail might not live on the same computer.
I should not be able to take over your life because I compromised your phone which has sms, TOTP app and email.
* use an interstitial page so that the actual activation is a POST request;
* send a confirmation code instead of a link
The password only makes this autentication less secure and it's not needed.
Recovery codes exist and are created at the time before recovery is necessary. But most people are going to lose their codes.
Who is going to remember what 3 things they picked out of 30 years ago?