Those upthread saying cell phones, I think you're stopping too short, its the internet. I'm a genx we had to develop face to face social skills, kids born in the internet age don't. They have chatroom, forums, games where all their peer to peer interaction is likes talking to an avatar and some fictional name. Now like what's been mentioned add in the the constant bombardment of porn, not just a hot naked girly magazine like we had, you can find just about anything to suit your needs and on top of that you can get it in 4k VR with options to order her around to do what you desire.
So now these guys who've been subjected to this for however many years, finally reaches the point where they want to court or meet a hook up and they have no idea how to talk to her, no idea how to flirt. Face to face interaction especially with the opposite sex requires keen signaling skills, body language interpretation being the biggest and when several generations of men whose only experience with the opposite sex is whatever porn they've been watching is a recipe for disaster. Not to mention the guy who is a 5 whose been watching porn with 10's for the past 3 years is under the delusion he can bag that 10 and when she shoots him down an incel is born.
Woman have a part in this too, many 5s think they are 10s, "you go girl" female empowerment, know your worth and the availability that was once there for guys is no longer there. many of these woman see influencers on social media, traveling all over, having very nice things that they want and no teenage boy or early 20's guy is going to be able to afford buying his girl chanel or dior enter the sugar daddy..
I'm high as fuck and just cracked open a bottle of wine so I'm probably rambling, I hope these are somewhat coherent thoughts as this subject is something I'm been thinking about lately, I recently started visiting reddit and the amount of threads by younger people on life dating virginly is astounding. A lot of pent frustration
Hope this made sense to some