Anecdotal, but my extended family puts the lie to that. Off the top of my head I can think of at least 6 stable couples with multiple, biological children, with a >12 year spouse age gap, both professional and working class households. Late millennial and zoomer girls seem to have a greater propensity for stable pairing with older, more established men.
I see a lot of average and downright unsightly, often older dudes with beautiful young girlfriends/wives. Usually that's because regardless of their appearance, these men are dependable and provide them with the sense of security, financially and in general. They aren't necessarily looking for the super-rich gigachad, but simply a competent man.
Many of the self-ascribed incels blame their genetics and looks for their troubles, even if they look perfectly average and with some work could be actually attractive. But that's the entire problem,
work. They're used to instant gratification. Eating whatever whenever they want, watching anime, playing videogames, jerking off, bitching about their problems on the internet - the idea of doing something productive that isn't immediately fun or satisfying over a long period of time, that may or may not pay off in the end, is alien to them.
It's probably true their parents failed them in some way, but it doesn't matter, you're an adult now and it's your life to live. You can choose to wallow in self-pity until the day you die, leaving nothing but crusty sheets and embarrassing internet history as your legacy, or you could try doing literally anything else. Ultimately, women are repulsed by weakness most of all, they can feel it. Clinging to your grievances and using them to justify inaction is exactly that. To be a man, one must first take responsibility for their own life at the very least, no woman worth being with would be interested in a manchild. Life can be scary, the world is full of variables and bullshit. But the only way to build experience and get better at it, is to live it. Opportunities aren't going to materialize out of thin air while you sit on your ass, at least for most people. Give yourself reasons to respect yourself, little by little.
It might be hard and miserable being alone, when nobody gives a shit about you, when no one supports you with even a kind word. But you only truly lose when you let it define you and completely give up. That's what identifying as an incel is, you shouldn't do it. Not getting any sex is hardly the worst thing that could happen to a person. In fact, some people wish it never happened to them, like incel mass shooters who regretably survived and went to prison for their deeds (Tyrone wasn't as gentle as Stacy they dreamed of).
As if incels are going to read this and change their mind, they've probably heard all this before. It's a deliberate choice they live with... Buuut, one can always choose otherwise before they're dead.
TL;DR: It's a
you problem, stop being a bitch.