The reason that singletrack has managed to live for this long is (imo) the forum.
It’s actually a great place with mostly down to earth conversations about, well, everything. The main reason it lives is the core user base.
If enough people leave there will be less content generated, meaning it’s more boring for the people who stay, who then leave, and so on.
FWIW I think what the stw guys are doing is the correct thing to do. I’ve been a magazine subscriber in the past for a year or two. The magazine really is great I should really subscribe again, but the main reason I come here is for the forum tbh.