higher prices would be a tough bargain i think, list price is already 15 dollars a month, which i think is pushing it. They already drop songs on the regular, the only way to make it worse would be to have less songs, i.e. even less worth the price. Recommendations are already a thing, but thats a different problem. Ads already exist, and they've already been memed on, though that is a free tier, so.
I can't imagine people putting up with much more, given that for fifteen dollars a month you could buying an entire whole ass album from a band that you like every month.