Because it's expected. Today's games, people kinda expect more voice acting so they don't have to read so much. Imagine BG3 with much less voice acting. Imagine the closeups, mouths moving with just text.
But that would have to mean that they would have to add some more content, right?
After all, if nothing is done with the content of the game, the sound materials from the original game should be enough for you.
