In addition to this, a lot of movies and TV shows are going to use the same DRM mechanisms, whereas with games it’s different for every game. The developers (both of the DRM systems and of the game) learn what works and what doesn’t work and adjust the system for their next game.

Edit: Also, games often have anti-piracy measures hidden throughout the game, so whoever is cracking the game likely has to play the game quite a bit to ensure they’ve caught them all.