I wonder if that's because this industry is more openly international, whereas DICE sticks closer to the Western, US-based canon employed by the Oscars. As an example, let's say a regular moviegoer might not see anything but Hollywood films for a whole year, with the rare exception of a foreign movie. However, that same description would be an unusual sight in gaming, where Japanese, European and global indie companies are essential to the market. If an association meant to represent the whole industry, doesn't give due credit to a considerable part of it, it runs the risk of becoming irrelevant. I think DICE might have suffered a bit of this: only two Non-American GOTYs in more than twenty editions.
You're probably right, and on top of that in gaming for as much attention The Game Awards gets, the enthusiastic gamers value the count of all different award publications to somehow decide the overall game of the year. That doesn't happen in movies where the Oscars feels like a culmination of all things.