I wonder if a solution would be a payment to extend copyright.

I think the strongest argument in the article is about the disappearance of works, but, as pointed out, this doesn't really apply to Mickey Mouse. Instead of having a universal expiration, which is causing some works to die, have a shorter expiration but then allow those who are still monetizing their works to pay a portion to extend it. This would provide a less grey market alternative to lobbying and perhaps the revenue generated could be put back into the arts.