To compare the price to that of a similar lenght mono hull...well, with a Tri, you get 3 hulls, plus the folding mechanisms, plus the rotating carbon mast, and the tramps. All that stuff costs more to make than the average mono hull.
The good news is you take it home instead of paying for a slip at a marina. Even with the added set up time you will still cover more water on the Tri, as you will be sailing twice as fast as most monos, and you can trailer it to a new area to sail, instead of seeing the same old stuff every time you go out.
I'm getting one...someday.