Most of them are cheap though. Like Spotify at ~$10 is nothing, you can barely get a beer for that in the city these days. That's far cheaper than you used to pay for CDs!
Netflix really took the piss though - with the charging for no ads, HD and multiple screens. Then it gets to like $30 a month which just isn't worth it with the diminishing library, so I cancelled that and use Amazon Prime Video for now as it's still cheap in my country (and has no ads for now).
Because they have to give that energy away in order to keep the grid stable.
Hopefully better battery storage will make this better in the future.
The aim with it is to naturally discourage people from overproducing in such overproduction times - e.g. maybe you disable your solar panels when you predict it will happen, lessening the sudden impact on the grid.
FWIW you could buy a high capacity home battery already to eliminate it yourself (charge the battery in those times), but they're still expensive.