Yeah. Search isn't the issue. Even inbox zero people archive all their emails anyway. They don't delete them.

Inbox 20,000 makes sense for a lot of people btw. Depends on your work and how important being organised with your email is to you.

Many people just declare email bankruptcy and don't care.

If you are on a very high number of emails, you can just archive the last 19,800 and go from there. And then unsubscribe from a lot of your key email offenders.