If you shut down all unsolicited email, you've removed a lot of the value of email in the eyes of most people. Prospective employers can't contact you, relative

If you shut down all unsolicited email, you've removed a lot of the value of email in the eyes of most people. Prospective employers can't contact you, relatives can't reconnect, and so on. Focusing on the bulk aspect makes a lot more sense. (Besides, if you don't want any unsolicited emails, it's pretty trivial to blacklist everyone and then manually add exceptions after you've agreed in advance to allow someone to email you. ISPs and such don't need to get involved in that, so they don't need to worry about it.)