Eh, 7/10 or 6/10's can get laid, the problem is they have to settle for a 4/10 or lower AND do work and wait to fuck them.
That's why pornhub is as big as it is. They'd rather just jerk off to a 10/10 instantly, fucking better than that 4/10 would fuck, faster than she'd fuck, saying things she'd never say. No time or money wasted.
It's a lot of work just to feel a wet hole, a lot of bullshit before and after. The work isn't the problem, the problem is knowing she's A.) not equal in looks (and usually she's not equal otherwise, financially, mentally, etc), and B.) never going to actually love you because she's been broken on other dicks, and the odds she'll declare you her master dick are slim to none considering even a 4 or a 5 woman can get an 8 or a 9 to fuck or blow him if she gets on social media.
I don't believe a 6/10 or a 7/10 is an incel, but a lot of them are MGTOW. They just did some market analysis and decided to buy imitation crabmeat instead. A 6 or a 7 can get laid, but they don't have the Amazon Prime pussy pass that 9's and 10's do with Tinder, etc. They have to work for it, spend time, effort, become "the boyfriend," and that embitters them knowing that other guys didn't have to do that, that she was a slut who had one night stands.
No guy wants to feel inferior, especially around a so-called girlfriend.