TC's appeal to people that camp but also need to trailer their horse(s), boats, etc.
(I know in our case initially, it was because I wanted to camp with my horse and so it was the only option.)
Although, I agree that the pricing is whacked - and pretty pricy, especially when you get into the slide outs and loaded option models.
Also, the marketing of the four season models for the AF990 at least for the year we have (2003) seems more hype than actual reality. I was expecting more insulation and some sort of efficient heating system in the tank areas, etc, but it's just passing the heat from the propane furnace when it's in use to the tank area - otherwise it's just the ambient air temp and pretty negligible insulation, as far as I can tell.