another aspect of this is, when is a game really economically unviable?

"abandonware" was justified on the premise that a game company wasn't making money on the game anymore so it's okay to pirate it. At the same time people kept saying, if I could actually just buy this old NES game, I would." Now we know for a fact, if decades after a game stopped selling you make it super easy to download and pay only 4 dollars for it, people will still enthusiastically buy and play NES games. Did the game actually ever become "economically unviable?" No, people were just waiting for the game company to sell it at the right price.