I don't think they want to grow sales past where they are at now. I know several folks wish they had cabs. I thought about it for a while, but I used to own a cabbed tractor. A late 70's IH 2500b tractor loader. Working in the woods, the glass took a beating. And there was no air conditioning, so in summer I had to remove the doors and back window or bake to death. In winter, it was nice, though. Had a little round heater core with internal fan, that was mounted on the ceiling. Hardly needed it once the transmission warmed up. But for the work I do, I want it open station in the summer. Plowing in winter isn't bad at all. I have the proper clothing. I ice fish as often as I can, and I'm used to it, and I just don't get cold. Plus, its so fast at plowing with the power angle blade on the FEL arms, I'm rarely out more than about 20 minutes anyway, and 10 of that is warming up the machine. I shovel the walk and steps, and by the time I'm done, the machine is warm and ready to go.
I suppose if I was a commercial operator with a blower I might want a cab.
It would be fairly easy to make a hard sided cab out of foam core and hang it from the ROPS. You'd need some sort of fabric skirt on the lower/rear section to allow for the total tilt and oscillation. I've actually hit the rear corners of the arm rest on the engine cover in full articulation and oscillation, that's how much the machine flexes. A hard cab would get shattered or dented.