We have owned 7 motorhomes in 32 years. Started out with a 20 ft Winnebago LeSharo in 1986, moved up to a 26 ft Class C , then to a 33 ft Class A. In 1996 we moved up to a 35 ft Class A with a big slideout. Since we were then full timing we moved to a 39 ft Class A diesel pusher. We found that the bigger coaches were fine when parked, and we loved all the room, but going down the road and finding campsites (particularly in National Parks) for large coaches was a bit problematic. So we started to downside, 1st to a 34 ft Class A gasser & then in 2006, when we were no longer full timing, we moved down to a 27 ft Class C.
The RV industry makes all size RVs because it's still true: "different strokes for different folks". Over the past 12 years we have lived in our 27 ft Class C for up to 6 months at a time. It has all the space that we need, including a walk around queen bed in the bedroom and lots of storage. It would be nice if it had more space in the living area (we have a dinette and a single chair) but that's a compromise that we made to get the queen size walk around bed in the back. The smaller you go, the more compromises that must be made.