We seem to have reached a bearable truce with spam. I think well north of 90% of email people try to send is spam nowadays, but no more than 50% of what I actually see on any given day is PR junk, unsolicited or otherwise. Granted, messages I care about sometimes get lost, but it doesn't happen often enough to make email useless. ML-based "native advertising" blockers will eventually become as common as spam filters, and the war will become a slightly unpleasant stalemate. Maybe the end-state will be something like current product placement in movies and TV, which is usually either comically heavy-handed, or completely unobtrusive and ignorable.