One of my best childhood friends fits this thread perfectly and I've watched his journey into being a 34 year old virgin.
1.) He was overweight as a kid so he get zero attention from girls and he had zero confidence
2.) Continued being overweight in high school and focused on playing football (OL of course) so much that he never went to prom or on a date
3.) Got hung up on a girl in college that is way out of hi league and never moved on until graduation
4.) Got hit on by an ugly slut in college and didn't pursue her for even a night because he felt some sort of chivalry towards said out of league girl who barely knew his name.
5.) Became an adult and got hung up on another girl out of his league who did text him back but anyone who wasn't an incel could tell she wasn't interested by the way she responded.
6.) Continue gaining weight until he is 5'9" 300lbs
My wife and I set him up with a friend and we doubled with them for his first ever date (he was 28) and it went well enough that the girl wanted a second, but the girl we set him up with had a similar body type to him and he rejected that instantly and never called her back. Now he's a grown ass man at 34 and his prospects are incredibly dim because he's been on one date in his life, and he has no idea how to treat an actual woman if he were to accidently go on a date again. The poor bastard has his bedroom in his 1br apartment completely decorated in a 7th grade male all sports all the time aesthetic. He has never read a book in his life and can't really talk about anything other than sports or action movies. He doesnt travel because he doesnt want to go alone so he'll only go out of town to sporting events with others. He refuses to use dating apps because of his confidence being 0 and says he would never date a woman with a kid.
This dude has a college degree, has been a teacher for over a decade so he makes alright money (relatively to some other incels), and he's a really nice guy so some woman would assuredly be ok with him being a bit immature in tastes as a grown man. He just doesn't give himself a chance and I'm sure there are plenty of other incels that fit into his category that just don't really know what to do or where they fit in society.