> ...but those who bought an early version didn't get whatever changes the new one brought unless they went out and purchased a new one.
And for certain groups (e.g., speedrunners), this was incredibly important. The example I'm most familiar with is Metroid Prime 1, where so many tricks and sequence breaks are only possible in the original NSTC release.
One could make an argument that having to seek out rare early releases to participate in the top tier of speedrunning is not a good thing. It's not like updates changing runs destroys a game's community, see the recently popular "Only Up" for a great example. One of the models used for a substantial part of the structure you climb was apparently not appropriately licensed and the updated route after it was replaced was significantly shorter. People kept playing, the same names stayed at the top of the leaderboard, the world went on.
That said, this also isn't inherently a problem either.
Steam has a feature to allow delivery of different versions of a title. It's intended mostly for test releases, but some games use it to allow players to downgrade to specific versions for mod compatibility (Kerbal Space Program) or to deliver a different tweaked version for specific use cases (Truck Simulator VR port). This sort of thing could be used in the same way to support the speedrun community.
Also there are games which have restored rare bugs intentionally to support speedrunning. If the bug was unlikely to affect someone playing normally and is important to the speedrunning community there's no reason it necessarily needs to be patched.
And for certain groups (e.g., speedrunners), this was incredibly important. The example I'm most familiar with is Metroid Prime 1, where so many tricks and sequence breaks are only possible in the original NSTC release.