They say it’s because they create a game around good gameplay and write the story around it later.
It is why I consider excessive use of cutscenes a tell of poor game design, They stop the machine and pull the player out of the environment. They have their place, but generally should be avoided.
book: tell a story
movie: show, don't tell (big sin opening lore dump)
game: do, don't show (big sin cutscene)