It's easy outside of gated platforms. The whole 'too hard to filter' hypothesis can be tested instantly by throwing OP's email body into an LLM
Subject: Your Passion For Homelabbing is Contagious
(Spam: 6/10)
Report:
Flattery to establish a connection.
Quick shift to product promotion.
friendly but lacks personalization.
Specific reference promotes their solution.
Calls for a response.
So even if buddy buddy spam becomes pervasive you really only have to decide how accepting your are of obvious sales tactics in normal comms. It may end up that everyone having more nuanced spam filters forces humans to use those same tactics less in normal comms.
One issue I see is that it’s much harder to employ an LLM defensively (for filtering) than offensively.
Welp.