Especially when you consider that 123 cells run about a buck each or so as is, and have a freakishly long shelf life.
Sure I wouldn't mind a replacement body for a classic series that took NiMH batteries, but look at it from their standpoint. Everyone makes AA lights, like the minimag. So for a xenon lamp, you are going to have to spend either a lot of time($) in R&D to either make a two cell light, that will cost more and be low performance compared to everything else they make, ex. E1e. Or, make a light that costs as much as other surefires, uses standard surefire components, and uses lots of batteries which people will complain about.
They have a huge market in tactical lights and equipment, and they are doing very well.