There is a certain kind of cow who hits it big in their early 20's and therefore carries their teen arrogance into their later life. Most of us were smug, dickish know-it-alls as teenagers who thought we were so much smarter than everyone else, but as soon as we were spat out of education and entered the workforce, we got a rude awakening. There are people out there who can do everything that you can, but better and with a better attitude. There's lots you don't know, and those old farts who were being square and conservative were actually doing it for good reasons. And then you will fail at something, maybe for the first time in your life. That usually comes as a shock.
For most people, their early twenties are a time of harsh lessons. It's not enough to be smart, to succeed in the world you need social skills, financial skills, negotiation skills, knowing-when-to-shut-the-fuck-up skills, things they don't teach you in school or college or university. Some people grasp those things faster than most, but they usually learn them by their late twenties or early thirties and go on to be successful at whatever it is they do. Life is a very effective but pitiless teacher.
But if the first thing you do out of college is a big hit, you don't have that experience. Even if (as in Lowtax's case) that success was pure luck and not really much to do with you, you maintain that teenage snottiness because "hey, guess what, 100% of the things I do turn to gold, I'm a goddam genius and anyone who disagrees with me is wrong by definition".
If you carry on doing the one thing you hit the big time with you can sustain that success (see: Yahtzee, PewDiePie, James Rolfe), or at least make so much money that any subsequent failure doesn't matter so much (see: Notch). But for many of these people, they fall for the narcissistic fallacy, and think that their success is not due to the successful things they did, but because they did it. That massive early success convinces you that anything you do will be successful, so why worry or plan for the future? After all, I'm me, and everything I do is amazing, so everything is going to be great forever, and if it isn't it must be someone else's fault, because I don't make mistakes.
But then their first big success fades, either because its time is over or because they actively fucked it up. And then our prodigy has a bit of a problem, specifically that of no marketable skills, and especially no interpersonal skills that will be needed for the next business venture. And because they didn't gain those skills in their formative years, and because they have colossal egos, everything they touch after the first success goes horribly South real fast. At first it doesn't matter, there's plenty of money and groupies, but eventually those successive failures start to bite. But that sense of invincibility hasn't gone anywhere, so they convince themselves that the failure of their subsequent ventures can't be their fault, because they always succeed. Look at what they achieved! So they rage and they flail and they blame everyone but themselves as their life goes down in flames. They don't move on, because they think they're too special to get a normal job, not that they have the necessary skills, qualifications or experience for it anyway. Then they get a Kiwifarms thread.
How many cows can you think of who follow this pattern? The once-successful prodigy brought low by narcissism and laziness - Lowtax, Spoony, Anthony Cumia, Cosmo Wright, Mumkey Jones, Movieblob, Doug Walker, Onision - that's just off the top of my head. You also see it off the internet - how many sportsmen, models or musicians got big at 18, never had to grow up, and then crash and burn once their star is no longer so bright?
If my theory is right, then we will see more e-celebs sink to full-on cow status. Look for people who don't do, or clearly don't want to do, the thing that made them famous any more but don't have the skills to do anything else. My money is on iDubbz, Ethan Klein and Angry Joe to join that list. They have largely or completely stopped doing what they got popular for, and are trying to diversify and falling flat on their faces in the process, as well as getting caught up in petty drama all the time. All aboard the cow train! Choo choo!