Did they really earn $4 a month per user when they used ads? I guess they raised the price a lot because they realised they would lose lots of people. One way to lose lots of people is to immediatly start with a high price.
It's going to be hard to get people back once they left.
Yes, there is lots of room for innovation. Too bad the big media companies have no feeling of need for innovation.
They lobby for laws against adblockers. They look to blame the customer and the ability of the customer to block their ads.