Spam assassin type solution is needed. WoT is a red herring, or band aid, as you rightly point out. Not much new here, spammers have been around for 3 decades at least. There are well tested counter measures. Many are already in place, but no one wants to admit it.
Discussion
If you’re wondering which solution should we be using to counteract spam: PoW or WoT, the answer is: sometimes one, sometimes the other, and sometimes both, depending on the context and the nature of the spam.
We avail ourselves of all solutions at our disposal. Abundance mindset.
#WoT 