Until the 20th century, genetic dead end males (though unfortunately, not enough of them) in the West were dealt with in a variety of ways, notably by being sent off to die in war or in the mines. It's time to start purging them again. When you don't purge genetic dead end males, and instead go out of your way to create a system which ensures that as many of them as possible get a girlfriend/wife handed to them, you get dysfunctional incel societies like India.
Ill push a bit here, and would offer a different framing, as I can somewhat remember the older internet.
In the early 2010s was probably when I first heard the term 'incel' online, on /r9k/. If you want a bit of internet history, the website
wizardchan originally was made as a split off from r9k, because the board on 4chan became too dominated by what people at the time called
crabs. Very bitter, and entitled young men, who basically make up the core of what incels are today.
We always had incels, and the term used to be much more inoffensive. For the people who started the website wizardchan, I can remember seeing debates about the terms and most of the original wizards being rather inoffensive. They didnt get laid, but most were nerdy, not obsessed with sex, not obsessed with women, and had moved on. Is a paralyzed man an incel? Sure. Are they a crab? Not necessarily. Debates like this were prominent at that time.
Something changed with /r9k/ and a generation of super entitled crabs obsessed with 'tfw' began to dominate and change the narrative.
As people pointed out earlier in the thread, it was communities like this which gave incels a voice and a shared sense of purpose and subculture which solidified the identity, and wed it with being a crab from everything I can see.
You know that meme with 'before internet, if someone wanted to fuck a toaster, theyd be called weird and not have a community, and now with the internet they have one"? Its like that, but with incels from what I can see.
What caused that metastasized change in men is another issue. But before the 20th century, 'dead end males' may have died- but also it seems even the incels of the pre-internet age tended to be more chill, from what I can see, and much less sex obsessed.
Maybe its porn? Dunno