Because „this is the only way to do it now“.
While Baldur’s Gate III launched in full last year, it did come to Early Access a long time before that. Over the time the game spent in its more limited form, developer Larian managed to gather lots of user feedback and data to be able to ensure the full game was delivered in the best manner as possible, and clearly it worked.
Now, talking about the future, Larian’s director publishing, Michael Douse, has stated that their next project will probably go down the same route and begin as an Early Access project.
