2 years may be a bit too drastic for many forms of content (e.g. books, music albums) where sales need longer to recuperate the expenses that went into making them. 10 years would seem okay IMO.
I would like to have copyright end once your earnings from a certain work exceed some multiple of the expenses that went into making it by a certain factor, but I can see that this is not realistic for various reasons.
> I would like to have copyright end once your earnings from a certain work exceed some multiple of the expenses that went into making it by a certain factor...
One of the reasons is that it would have a chilling effect for speculative investment in creating works. What if I'm a movie producer getting an average of one hit for nine flops? I need the profit from the hit to subsidize the flops.
I would like to have copyright end once your earnings from a certain work exceed some multiple of the expenses that went into making it by a certain factor, but I can see that this is not realistic for various reasons.