I support letting companies keep their copyrights on the grounds that it will be a lot easier to get this actually passed, and in the grand scheme of things, Steamboat Willie is not what we want. Steamboat Willie doesn't matter. What matters is the 99.995% of the rest of the stuff done in the same year that Steamboat Willie is shielding, the stuff with zombie owners, the stuff with owners that don't really care, the stuff that you simply have to presume is owned by somebody, somewhere, who may sue if you try to use it yet at the same time there is no practical way to find out who these people are so you could seek permission.

I also support continuously raising the price necessary to renew the copyright as you try to carry it longer and longer. And again, I'm not trying to hurt the mighty Disney corporation; sums they'd laugh at would still be sufficient to open the bulk of the content back up to us, and that's what I care about.

To make my point clear, this is entirely practical. In theory, should Steamboat Willie be public domain by now? Yeah, sure, there's no really good argument based on the public interest otherwise. But as a practical matter, if we could distinguish between Big Copyright's interests and the vastly larger "everything else", we'd be much more likely to come to a compromise that leaves everybody reasonably satisfied, if not ecstatic.

I don't want to speak for the OP but he's probably referring to the character Mickey Mouse, which is already protected effectively in perpetuity by trademark law. So there doesn't seem to be a reason to distinguish copyright terms on that account.