It could be that these big RVs have always been owned, but were previously just parked in the storage lot. Now that more are out of work, or are forced to hide (especially the West coast persons) from an unverified virus yet to be identified and are free to travel more, or forced to work from home (or the rv) and are able to take more frequent or longer RV trips that we are able to see them on the road.
It always amazes me how many campers and rv and boats just sit in the same storage lot 51 weeks out of the year anyway. Seems like it would just be cheaper to rent an rv for that one week a year that most use them. I guess it is fun to own the dream though, to know it is yours and there waiting for your adventures.