This is sort of like the lover of an old book whose author has stopped reprinting it wanting to preserve the book for themselves.
I'm definitely on board with copyright terms being too long and, in most cases, "abandonware" doesn't have a lot of value for the original creator anyway, but abandonware isn't primarily a big corp issue.
So I could write a good book now, publish it, let it go out of print as of this year, live another 40 years. You wouldn't be able to get a copy of my work from the public domain until the year 2127.
Flip it: Public domain happens by default. The problem is that some very powerful lobbyists ensure that the government declares otherwise for ridiculously long (and constantly increasing) periods.
It has to be one of the sickest corporate abuses ("anti-consumer, anti-society") in US history.
Lets say you require renewal each decade (with a one year grace period)... The first registration costs $100, the next 1000, then 10000, etc. If a company is literally willing to pay tens of million+ to keep a work out of public domain for more than 60 years, let them. This allows you to get the first 30 years for $11,100 before it gets pricey.
Frankly, I like this idea. Get rid of the pretense of public domain as long as a company is willing to pay that much a decade. Maybe just have it 2.5x each decade once you hit 100 million. Also, have a 3-5 year grace period for renewal before it becomes public domain.
Keeping something public yet out of the public domain should cost.
Personally I just go with anything over seven years is public domain, unless I have a strong urge to support the artist(s).