But it's trivial to write a slightly different implementation of something.
I think one really has to consider what the effect on innovation will be - you don't want too many protections as that will stifle innovation as it prevents people from building upon the prior ideas, but equally you don't want no protection at all as that will discourage innovation as R&D takes money, so if you can't recoup the investment the money simply won't get invested into R&D and the innovation won't happen.
It's not like the artists got most of the revenue from CD sales either. Artists being scammed by record labels was so common it was almost a meme.
And yeah they agree to revenue-share because it's much better than the alternative of piracy and no money.
I think many of the people complaining don't remember what is used to be like when you would pay £10 per album.