How is spam an existential threat to email? Spam filters have gotten exceptionally good, to the point where I find it hard to believe that anyone using a decent filter receives enough true spam in their inbox to make them stop using email altogether.
I use the default GMail filters - perhaps I'm just lucky and receive easily filtered spam. I get hundreds of spam messages per day, and none break through on the average day.
Hundreds a day sounds plausible. So with that much crap to wade through, how long does it take to finally discover and rescue false positives from the spam folder?