As long as there are people willing to preserve it, then we will preserve it. Few people would ever "stop" efforts to preserve something, it's just going to stop being preserved when there is no one around who cares about it anymore.
There are many millions of paintings that have been lost to time, and there will be many more.
Just because something isn't preserved doesn't mean it is worthless. The transience of human creativity is part of what makes it so beautiful.
If the Godfather was to be removed from existence this instant it would still have value because it has already made a mark on the world and the memories of the people in the world. And will indirectly influence generations to come. Value accrues in the humans who experience the work, not in the work itself.
Those laws exist to protect the rights of the creator for a period of time; if they want a thing to pass into history, without openly publishing the source, that's their prerogative.
Even before copyright expiration, anyone can clean-room reimplement a thing in open source if they wanted to, and not be violating copyright. This has been common in OSS. (Samba for example)
The period is effectively infinite now, since congress keeps retroactively extending it.
Also, the SMB protocol does not contain any copyrightable material, like music, sprites, icons, game assets, etc. Copyright law prevents you from faithfully cloning (pixel for pixel) most GUIs and games (so most phone apps)
The Sonny Bono act was passed 19 years ago. 100 years of protection isn't infinite. It also requires an entity to WANT to enforce that copyright. if they exist, then you really don't have a right to pixel clone something - they can keep it buried.
There are plenty of game variants created that capture the feel of prior games without being IP violations
There are many millions of paintings that have been lost to time, and there will be many more.
Just because something isn't preserved doesn't mean it is worthless. The transience of human creativity is part of what makes it so beautiful.
If the Godfather was to be removed from existence this instant it would still have value because it has already made a mark on the world and the memories of the people in the world. And will indirectly influence generations to come. Value accrues in the humans who experience the work, not in the work itself.