I suppose one difficulty is that DOS games were released before the DMCA, or before the DMCA's process was clear. And the old system wasn't so forgiving.
You just described archive.org ;)
The first, information asymmetry. The person holding the code (the lone developer with an old floppy disk stored in the attic) has no idea who the owner might be. The actual owner is well aware of what they own.
That could be resolved by a DMCA takedown notice, yes.
Alas, there's usually also financial asymmetry. And as an individual, the potential costs of a copyright lawsuit are not something you want to face. As a larger company, it's just part of your normal expenses - especially if your business model is "accumulate IP"
No, because while it may be difficult for you to determine ownership, the actual owners may be well aware of their IP.
>Throw it up on a free service somewhere and respond to DMCA takedowns in the rare event the owner shows up out of the woodwork.
The DMCA protects the free service, it doesn't protect you.
Prior to that their liability wasn't a clear legal question so there was alway lawsuit potential.
Archive.org could still end up in more trouble under the DMCA because lawyers could argue that there's a pattern of violations and it's not a neutral carrier.