No spare seems to be the trend in cars but I would not be comfortable without one in a motorhome. We spend some time in places where there is no cell service and I just can't imagine driving without a spare. Call me old fashioned.
Or, maybe just call me a guy that has had to change one of those big tires himself because there was no alternative. Or, try buying a matching tire to replace one of your six when you are away from home.
Save weight? A 16 inch E rated tire and wheel probably weigh about 60-65 pounds as I recall. About what eight gallons of gray tank sewage weighs. After all, these start out as TRUCKS (assuming Ford chassis models). Surely 65 pounds is not that critical. Like the old ad said "Don't leave home without it" at least for me.
Paul