This might be true for games, but its not universally true for software.

Clearly the Windows NT kernel is older than 25 years, and is still making money.

And it's not alone. My own company is still actively developing and selling a program first released in 1998. Even if we wanted to Open Source every build 25 years after it's release, it might be difficult to figure out how to store the code that long.

We originally backed up on tape. Good luck restoring that now. Then writable CDs; those have likely degraded (and we'd need to find an old CD Drive to read them.)

Even most hard drives of the era are no longer usable - MFM, SCSI ,ATA none of those interfaces exist, and drives were tiny. If you had to choose a media today, that you'd be confident would work in 25 years, what would you pick?

Sure, our active code survives because we simply clone the archive every time we replace the server, but we don't have a history if every build ever.

Seems like a million years ago I wrote some games. The source code is long gone. (Well it's on 5.25 floppy disks in my garage for 30 years, so functionally gone.) The compiler to make it is long gone. The OS and physical hardware is long gone (although emulators exist. ).

I'm sorry to say, but making laws for old software is basically pointless.