It's minimum wage in California, where he lives. The rest of the US is half that. Although, Alex lives with mommy and daddy I think, so unless he pays rent with utilities included, he really doesn't have any expenses beyond, I assume, Unity. If this is the case, Alex could make 0$ and still lose nothing from making YandereSimulator. This whole argument is totally disingenuous because most people subscribed to him probably wouldn't buy the game and many of them are people who just like to troll YandereDev. An 100% transition from interested parties to sales is a marketers incredibly messy wet dream. Also, his main demographic is teenage girls, who would be too young to buy the game, and probably don't have $20 to buy video games, or the PC to run it.
Most importantly, Alex wasn't always earning minimum wage, at one time he was earning three times that amount. It's perfectly reasonable to believe he did stretch out development because he was making 6k a month from it. That's 72k per year, which is above the average salary in California of around 63k per year. And the only reason he's not still earning this amount is because of his own foolishness and slow release schedule, so he can hardly pretend to be hard-done-by. He's not even earning minimum wage, the guy has deals with porn games, he has YouTube ad revenue and donations through Twitch, he's likely still earning a comfortable living.
He wouldn't even earn the amount of money he thinks he would from YanSim, it's a buggy mess that's easily reverse-engineered and cracked, even if loads of people bought it, Steam takes 30% and then California would take a good chunk of the rest. Then people would just pirate it, break it open and mod it to try and fix the game, like Skyrim. Only more irredeemable.