It turns out that making a machine that is capable of determining the difference between actual legitimate messages and messages pretending to be legitimate is a really difficult problem to solve

That's a very interesting take. Gmail has always had one of the better spam filters in my experience. I absolutely remember when common wisdom was that if you were inundated with spam, one way to help was to forward email to a gmail box and have its spam filters run on it.

Even today, I see very few false positives and false negatives.

YMMV of course.