And I'm not that surprised. Not to over generalize but very few suburbs are walkable. Once you're in the car what's an extra 10 minutes on your drive? As a person sitting in the city pondering a life outside of it I can't see the point in the suburbs if I'm going to be driving and stuck in traffic anyway. I'd rather go whole hog and live rurally.
Rural setting doesn't have anything like that.
I've though this way too for a long time, both now and when I lived in a city. Having thought about it often, I think the two things driving suburbs are those with daily commutes (that 15 extra minutes twice every day adds up), and many people are not well off enough to live in the denser city to begin with (as things stand). Cities are economic attractors, and suburbs are basically less concentrated instances (or addons) of that.
Also note that the question specifically says "amenities". Likely most people aren't thinking about commuting while answering the question.
The reason people in the suburbs are moving to even bigger houses is because they are getting older and richer, or their families are growing.
Once you start playing the space game, particularly if you're in a location where you tend to get guests, it's always appealing to have another room.
I think you are reading it backwards. 44% suburbanites would prefer to live in communities with smaller houses.
Same can be said for large suburban houses.