Well, games have been around for a far shorter time period than movies, so you're not comparing games from 1920 to games from today (and thus the overall effect of inflation is lower). Also, since the former #1 game (BLOPS 2) came out just a couple of years ago, and GTA V beat it by 60% on launch ($800m to $500m), inflation didn't play a significant role.
That just takes the argument in circles since the former #1 might not have been the inflation adjusted #1. It may be the case since "launches" weren't always such a big deal.
