Nostalgia is essentially a good thing; you can remember the easier times when you watched cartoons in your pajamas on Saturday mornings, the first time you kissed a girl and the awkward, teenage relationships that followed, the times when having a fight with a classmate was the greatest of your worries, and by your fondness of these small moments you keep the positive memories of your young days alive, you want to share them with your children by helping them have good memories. Not going to powerlevel too much, but I worked with children for a while, and it was a very nostalgic experience - everything from the bloody noses to the collectible cards and the "teacher, Martha kissed a boy!". Nostalgia is essentially a way for your brain to teach you how to behave with developing children, a big influx of serotonin associated with the moments that helped you grow up in a positive way, making you want to recreate them with others.
Admittedly, it also comes with negatives - if you are a very sporty guy, and your favorite memories with your dad are playing baseball with him, and how he encouraged you to join the high school football team, if you have a nerdy kid you aren't going to be disoriented, you could be downright disappointed. And that's where you get the shitty parents who pressure their children to do something they used to do, not as much in a "he is going to succeed where I did not" but in a lighter, less competitive "I am going to cheer for my kid at the little league game, goddamnit, because I am a good dad!".
The thing is, this sort of pressuring kids into becoming what they aren't is much more common, in my experience, with parents of single kids. Large families don't have a problem letting their sporty kid be sporty, their nerdy kid play Magic, their rebel daughter go full Daria and their cheerleader daughter experiment with makeup. It's single kids who tend to show up to events where they clearly don't fit in, and do not want to fit in. Not only is that bad for them because they are wasting their time, but it also messes up with them in the long run - again, in my nonprofessional experience - they tend to grow up into adults who wait for others to tell them what they are supposed to do, what they are supposed to enjoy. They are not assertive in their desires because they internalize the idea that what they want to do is inferior, that their inner compass is broken somehow. Thankfully, unless the parents are especially demanding, usually their personality asserts itself.
Leaving this aside, I wonder if Kevin is just the next logical point - the movement of nostalgia from the one-child-parent to the no-child-parent. Now I have zero problems with people who, for one reason or the other, want to go without kids, and I realize that not all of them are Kevins. I figure that most childless people will still have family and community to satisfy their need to pass on their experience, or jobs like what I used to do. And for others nostalgia may not be an especially strong motivator to begin with, and that's fine too. But seeing Kevin, I suspect that he is making himself into his single kid in order to satisfy his nostalgia, that he is giving himself the life he thinks would be optimal for his child. Like his mom let him grow up on the internet, he is parenting himself to let himself grow up on the Internet. Like his mom let him watch television for hours at an end, Kevin lets Kathryn watch cartoons and play with toys. And Kathryn needs to stay a kid, so Kevin can keep sharing his meager life experiences with "her" - because unlike sharing your experiences with an actual child, there's no positive feedback from Kathryn to Kevin. Kathryn doesn't enjoy playing with toys, barely touches videogames, and calls twitter a "hellsite" - because Kathryn is Kevin, a fully grown, balding man who is old enough to know better. But there's not going to ever be a Kevin Jr. now, and Kevin is barely even part of the community of people whose house he lives in, so Kevin only has Kathryn.
And they remain in their room, hoping the next toy will be, finally, a fun one.
Kevin has finally broken the $5000 barrier for e-begging. Congrats, Kevin! 
