not just for the obvious capitalist evil reasons but also just because how much of it doesn't fucking work at all. no matter how much RAM my phone has it still can't juggle Pokemon Go and music/a podcast. my google shopping list just stopped updating itself for absolutely no reason. random shit just constantly goes wrong and there's absolutely nothing the end user can do besides hope a fix is pushed out that doesn't break anything else
Install Firefox, open Youtube, set "Use PC version", then it would play in background.