I feel you do this quite nicely. Personally I think if I had bought such an old game already on physical media decades ago, I’d just pirate it now. I can see the argument though that GOG (or Steam for that matter) delivers tweaks that make old games work on new hardware though, so that is worth paying for. Guess it all comes down to pricing, I wouldn’t be willing to pay full price for just a patch that makes it work on current systems.