[majormajor]

My recollection of the term incel is that it was a self-applied label, not one created from outside the group like your "involuntarily not rich" hypothetical. (Even in that example, though... who's going to tell you you're wrong if your theory is "nobody should simply expect to get rich for showing up and not putting in the work", exactly?)

As to whether or not that group is popular... this is an interesting one since the bonding factor is a lack of relationship success (which is closely related to, but not the same as, popularity) in the first place. But if you look at a lot of how the group that has gathered under that label interacts with the rest of the population... it's hard to say it's just something like mocking them for not being able to get laid. There are a lot of frankly offensive and violent theories pushed by people out there.

It's deeply ironic actually - "I'm not having sexual success, I'm going to start listening more to other men who also have the same problem, they're the ones who will be able to tell me about women." Back when it was a more ironic, non-violent "foreveralone" meme I was in the club... it wasn't increasing my exposure to men that eventually got me out of it.