Very few premium brands left. New Horizon but very heavy and very expensive. I beleive Spacecraft is still around as well. Both you have the option of having custom built units. CEO of Keystone once said they build more RV'S in a week then New Horizon builds in a year. Most of the premium brands are gone. I still beleive Artic Fox builds a better RV at a more affordable price. DRV has been purchased by a conglomerate but I think they are still built better as well.
Maybe some others can chime in with more independently owned RV manufacturers.
With maintenance and repair work I can get 15 to 20 years out of Keystone or Forest River products that don't stress the budget. I have no illusions of what they are. After about 10 years the interiors are out of date anyway.