It's a product of (1) game start time and (2) we're such consistent winners that the opening round is no longer a novelty.
Just looking at ticket sales, it's going to be an upper-30,000s crowd, I doubt anyone will even notice that there are a few thousand unsold seats. It will be a loud, energetic crowd.
I don't blame people for waiting for the NLDS/NLCS (if we win...).