Yes. That's the selling point to a legacy game.
The only selling point is that events in one game shape all future games. So far that's been through destroying game pieces (e.g. Ripping up cards), writing on maps, and placing stickers over things. Conditionally released new components are another element, as is altering the rule book itself.
I -think- those are the constants.
I think Pandemic Legacy has been the only "once and done" legacy game. So far at least (although there is a growing niche for single-campaign/play games it seems).