His reasoning for why movies are more boring was simple: money.
A production team is looking to distribute their movie in as many channels as possible, and with the broadest appeal possible. As a result, you see a film made with the broad strokes but lacking in subtlety. If a film might be challenging because of the subject matter, the complexity of the dialogue, the character development, or the plot then it gets dialled back.
You lose the specific cultural references that give a film it's charm and it ends up not really being a true reflection of any people anywhere - just easy Friday night cinema fodder that maximises return on investment.
A movie sucks because it isn't art any more.