One reason I keep pounding the drum for MTB conversions is that you get a lot of value for the $$. For buyers on a very limited budget, older rigid frame mtbs are out there, at attractive (low) prices. Put a little sweat equity into it, and you have a nice riding bike. Most of the people I see riding bikes are what I would call recreational riders, just looking for something decent to ride for exercise. A second group are those riding around campus or commuting. For both of those groups, the weight and speed penalty of a MTB is no big deal. And the ease of adding racks, fenders, wider tires, etc., are all real pluses. Instead, I see a lot of these buyers buy some POS road bike instead, with craptastic components, no faster, and no lighter in weight (often a lot heavier).