> (how many valid emails have you found in spam in the last 5 years?)

Personally, running SpamAssassin, zero.

However, this seems to be getting worse with the big providers deciding to drop domains they don't like from time to time. Selfhosted email will work for 4 years and then Google or Microsoft will spam them for a month for no reason. It always starts working again because I assume that what they are doing is technically anti-trust and running it for too long would make it obvious.