Yup, this is the real reason. When you’re a kid/teenager, you don’t realize just how much free time you have to spend on stuff like video games. Then you become an adult and have way more responsibilities, and suddenly video games just aren’t as appealing as a time sink as they used to be.
Not to be a downer but… how did people not anticipate this happening? Google is likely going to do everything they can to shut down non-official clients like Piped, since they’re sidestepping all of YouTube’s revenue streams. Hopefully they don’t take the nuclear option and somehow lock down the API and make it much harder to download videos via tools like yt-dlp.