Never has a copyright infringer been brought up on theft charges.

It is not theft, no matter how much you claim that it is. If I duplicate and distrbute a work you hold copyright in, I have not "stolen" anything from you. I have infringed your copyright.

This is the problem with using "intellectual property" as the terminology. It incentivizes rightsholders to hold the mindset of "ownership", as one does with property. Copyright is a limited term right, after which the rightful ownership of the public enters the picture.