It would discourage companies from buying and hoarding old IP, but as far as I can tell, it's only Disney that is both doing that and over the net worth threshold.
Hell, they could probably avoid the penalty altogether by breaking off parts of their company into smaller companies.
Hawley's Disney revenge bill limits copyright to 56 years for major corporations:
There's a clause limiting it to companies/people worth more than $150 billion and that produce substantial works...
Finding someone to replace him is going to be a trick. You'd have to find someone who wants to be PM enough that they'll do it despite the massive drawbacks the position currently has (party approval in the toilet, having to deal with multiple crises including several of their own making)