People who are full timing or spend winters in Florida or down in the Rio Grande Valley can really take advantage of the space and conveniences of a big motorhome or towable - you can't beat it. A small RV like a Class B is not suitable for these purposes, although I suppose there are some people doing it for their own reasons.
Travel, however, is a different story, especially for people who have an active travel style. A small RV can actually be a more comfortable way to travel around the US and Canada, visiting our national parks and monuments and beautiful cities and towns. Why? Because you have the conveniences and comfort of an RV with you all day long. You always have food and drinks handy, a bathroom, access to medicine, extra clothes, sporting goods and a place to eat. Big rig owners run around all day in a car and don't have these advantages.
When we are on a trip, we normally leave our campsite at say, 9 AM and are out and about all day sightseeing, hiking, browsing stores (my bride's favorite sport) or whatever. We get back in the afternoon usually around 4 O'clock. Then we enjoy a drink outdoors, take it easy for a spell and eat dinner. After dinner we go for a walk, then go into the RV for the night. We will read, watch TV or a DVD then go to sleep, pretty much the same routine when we are home. So you can understand why the space and comparative luxury of a big MH don't have a payout for us. We don't want to sacrifice the convenience of the RV all day for just a few hours in the evening.
I am not criticizing the big rigs, they are the right solution for many people. On the other hand, bigger is not always better, and a small RV does offer many advantages for extended travel.