I feel this. A few years ago, I made a joke app[1] which got a bit famous on campus back when I was in school, and the process of getting it on the Play store was literally harder than writing the darn thing. Nowadays, it even got removed from the Play store for some reason. I couldn't imagine running an app for a living where you have to deal with absentee/abusive parents like Google and Apple just to put bread on the table.
Cool app and congrats on the users! 400 ain't nothin' to scoff at :)