Yeah, I feel that way about all entertainment. I don't want to be watching 8 hour movies, reading a book for six months, or sitting through 20 seasons of a TV show. There are so many entertainment options, it seems crazy to spend so much time on one thing.
I'm currently enjoying Witcher 3 but at the 80 hour mark I'm seriously considering finishing Hearts of Stone and then taking a break before tackling Blood and Wine.
Yep. The only games that really pull off being "long" well are the ones that let you do as much or as little as you really want.
Elder Scrolls is usually the go-to example. It's easy to be aimless in those worlds. There are main stories, usually not overly long, and a heaping pile of side content to do. But you get to play how you want. You're not railroaded. Unless you're a hardcore completionist, the games don't make you feel like you're missing anything by not doing every faction, every sidequest, etc. Eventually you just reach a good place to stop, but usually in the process you feel as though your character told a story.
Valhalla was just a chore. There was basically a single path from start to finish and that path took >100 hours to get there. I couldn't make it to the end. The result is that, even though I played over 50 hours, I feel like I never really played the game because it never ended up taking me anywhere. There were some places that I did want to go and explore because they seemed cool, or some quests that I wanted to keep going with, but I'd get walled by sudden level spikes, which just felt crappy. It just turned out to be a waste.
I don't think there's a backlash against shorter games. Ubisoft found a formula that has kept people playing their games for long periods of time, and if anything, there's a backlash against these long, collect-a-thons.