Maybe it has something to do with people viewing games by their utility rather than by their artistic merit? The two mindsets contextualize length very differently.
And even the same person can do both. I buy a new FIFA game every year because i'm guaranteed to put 200+ hours into it. It's not great artistic achievement, but i play it enough that I roll my eyes at the people who make comments about people paying $60 for a "roster update". It's easily worth it for the gameplay changes (which are always going to seem minor to outsiders because its a sports simulation).
On the other hand I paid full price for Brothers: A Tale of Two Sons and thought it was well worth the money, even though it was a single-sitting experience.
I understand the intention of the thread but feel there are a lot of false premises in it. Specifically on film length, we don't count the minutes, but there is a sort of minimum requirement. You wouldn't sit down in a theater and pay full price to watch a single music video, or a 7 minute short film. Would you?
So it's a poor comparison, theatrical releases are already a self-selected grouping - one TYPE of cinematic experience. There are clearly plenty of others that wouldn't make sense or generate profit by being shown alongside The Avengers.