[Videx]

could technically count as copyright violation.

Yes, or not. Where the bigger crime occurs is when an author disappears entirely, and others, in a misguided attempt to protect this unclaimed "copyright", forbid anyone to modify and distribute it.

And so we're stuck waiting for someone to come along and claim to have written all original code to do the same thing. Of course, there's only a few ways to perform a function in a given language, so there's a very good chance a large part of any new code will look exactly like previous code.

Coders drop dead (or drop out) all the time. Let's put some reasonable amount of time on limitations. Maybe 6 months.