Game development used to all be "project-based" . Projects have discrete beginnings and endings aimed at developing a game which was then released, completely debugged on a cartridge or disc. Following this, a team would then move on to another project. As a developers, I always felt a bit of sadness at shipping a game I'd worked on for many months and starting fresh from scratch on a new one.
With the spread of the internet in the 90's, PC games had the advantage of allowing upgrades and expansions after a release and a few developers stayed with a game for its entire life. Some popular MMOs have support crews fixing bugs or making sure the game keeps up with the latest OS changes many years after their initial release. Digital distribution platforms such as Steam have built upon the PC's strength of connectivity and openness to allow many developers access to popular online marketplaces with incrementally released games.
As consoles gained internet connectivity and local storage, we started seeing a similar adoption. Often, it wasn't a good thing for players. Day one patches became a way for game developers to push off bug fixes and optimizations. This forced players to wait hours for updates to be downloaded before they could play a stable and polished version of the game.
Mobile games have pioneered the live game model and open marketplaces by offering cheap or even free versions of their games, which are monetized through advertising or by selling add-ons which enhance the value of the game, etc. Console and PC games have been slower to catch-up with this model, but as players are becoming accustomed to the expectation of continual growth of their games, it seems the market is changing to adapt to it.
As games and teams transition to live models, the term "project" has less meaning. Schedules, budgets and feature specifications become more fluid based on the day-to-day key performance metrics rather than fixed up-front profit and cost projections (aka guesses) from a marketing group. Rather than the approach of stuffing every conceivable feature into a single release and hoping that some of those features will drive sales, many AAA game developers are approaching a "Games as a Service" (GAAS) model of releasing a Minimally Playable Game (MPG - a variation of the Minimally Viable Product approach) and keeping teams together to release add-on features based on how the market reacts.
The project approach may be coming to an end.