That is not the only point he is making - he is saying that if they had known Apple would be changing terms in the future to harm Spotify's interest, they would

That is not the only point he is making - he is saying that if they had known Apple would be changing terms in the future to harm Spotify's interest, they would have thought twice before releasing an app for the ios platform and add value to it. His valid point is that it is apps, like his and many others, that also really added value to the ios platform. But Apple is now ignoring that factor and pretending as if Apple is solely responsible for making ios an attractive platform for users, and so thinks it can dictate terms as it wants. Let's not forget that the reason the Windows Mobile platform died was because no developers cared for it. And others like Tizen OS or Sailfish OS struggle now with the same problem. Apple should be happy that idiot developers are willing to pay it $100 every year (which is also too high and should be a one time fee in my opinion), rather than trying to gauge its developers for money it doesn't even deserve. It also screws their users because ultimately the developer passes on the Apple Tax to the user.