GM started building the front-drive Olds in 1966, front-drive Cadillac in 1967, using the Olds-developed drivetrain package but with Cadillac engines instead of Olds engines. Cadillac has been making front-cars ever since, Olds was making them as long as Olds was making anything.
The Olds-powered drivetrain found its way into the GMC motorhome, 23 to 26 foot. Early models got the 455 Olds, then the 401 Olds when they stopped making the 455. GMC motorhome was discontinued before GM went to corporate engines replacing each division making their own.
Revcon (which has made a lot of things other than motorhomes) started building a front-drive aluminum shell motorhome in 1968 using the Olds Toronado drivetrain. They kept making front-drive vehicles using this package until it was no longer available with large enough engines, then built their own drivetrain for the next ten years. The one you direct us to is late enough vintage to have the Revcon drivetrain rather than the Olds. It still has a lot of GM parts, like the Chevy engine and a large TurboHydromatic transmission.
I've seen Revcons from this era parked in fields, as well as contemporary (but fundamentally different) FMCs. I don't see many in campgrounds or on the road, and I think people buy them as restoration projects and get discouraged. A restored, fully functioning Revcon has to be really worth something, like a classic limited production luxury car.
I see more GMC motorhomes in actual use, not often restored to vintage condition, just in usable condition. I suspect as a project, the GMC is less expensive, and there were more of them made to serve today as a supply of cannibalized parts.