I don't know Emmett, but if he was totally set in terms of wealth, and if the main thing keeping him there was because it was satisfying work, well, then he could quite reasonably decide that doing something less demanding so that he could have the spare time and energy to be a very good father to his child might be more satisfying. That's certainly the decision I'd make.
CEOs are not a lot of people. By definition they are extremely few in number, and those who become CEOs of top companies have a perhaps pathological drive to get there. For someone like that, an entirely predictable event -- like the birth of a child -- is the last thing that would make them sacrifice the position they've worked so hard for.
Now would I quit my job for $100 million? Absolutely! But maybe that just means I'm most people...
It's like continuing to play your Civilization game for "Just... One... More... Turn..." after you defeated everyone and you're the only civ left.
So you get into the office (maybe) at 10am (maybe), reading some emails, firing off some responses, maybe taking a call or two. Then a ritzy lunch for an hour. Coming back to some more emails and meetings.
Some days you will be putting out fires all day. But the more mature the company is the less you have to do that. After 15+ years the company should have a mature executive team that can handle all but the biggest fires by themselves.
Most people reading this site are in the 1% of the world and could easily retire to a lower cost of living area right now or after a few years of saving. They usually don't: Firstly, because the drive that gets you to earn that kind of money also keeps you going. If you're used to and can handle 80 hour weeks, going to 0 is likely to make you feel unfulfilled quite fast (which is also why I don't fully buy the child story). Secondly, you always judge yourself in regards your friend group, and usually quite badly. This might seem absurd to us, but they might be looking at their friends with private jets, yachts and paintings valued more than their total net worth and not feel like they are at the top.
There are exception, of course, but I doubt you'll find many of them in the extreme environments at the top of the business hierarchy.
But if you've banked $100 million, that's a totally different world. You have wealth that grows by itself passively, and you'll never be able to spend it. You can live wherever you want in the world and never have to work, and neither will your offspring for multiple generations. Any work you do at that point is firmly in the "Play the video game after you won" territory.
It’s not the “position” he worked so hard for, it was to build a company. Being CEO is a means to doing that, not the end goal. He did that, it is extremely successful, it will probably continue to be successful without him.
He even says it in the article - that for a long time, he wasn’t sure if he could leave and have it continue to function well. As someone who started, ran, and sold a (much, much smaller) company, I understand that viscerally. If you’re somewhat tired of it, it can feel like you’re trapped. But then you work on that, making sure that the things you do get well covered by someone else. And then, one day, there’s nothing it needs you for anymore, and you’re finally free.
I'm certain it happens once in a while when someone has a personal realization and decides to change their life's trajectory fundamentally. Maybe their own (role model) parents died and they discovered that time with your children cannot be substituted with gifts and money.
Now in this case it's unlikely given Twitch problems but sometimes important humans are just humans.
Additionally, you rarely hear the actual reason for someone quitting from a position like this; there will nearly always be a nice cover story. Being honest this time around, especially given the actual problems the company has, seems unlikely.
I'm not saying the child was no factor, but intuitively it seems quite unlikely that this is the full story.