I don't think this is a good idea, for two reasons:

They push the responsibility of getting rid of unwanted stuff in our mailboxes to us. It's not a single company doing this, but most of them. That's sometimes dozens of emails a week! We shouldn't waste our time reading, parsing and fighting the unsubscribe forms - many times fortified with cookie-consent walls!

The average internet user will not do that anyway, so the spammers rely on user's laziness and dulled senses, just like ad blindness, so they slowly start to accept this sick situation as the new normal. For us it becomes the new normal. For our children - the only normal.