Right, and I think boxing oneself in is just the point of the M Monochrom. Those who might previously have shot only black & white film voluntarily boxed themselves in, so to speak. Yet this is often an advantage in staying on track with "seeing" in black & white. And the MM, being dedicated to this purpose, appears to be very good at it....So, to repeat, I may be a weenie, but for $8K, I want a camera that essentially gives me my choice of whether to go color or B&W. Don't want to box myself in....
Others, who might carry a second camera loaded with color film, or a second medium format back with color, would be more aligned with your view and prefer to have the choice at the time of shooting. These folks (along with those who shoot only color) would show little interest in the MM, and prefer the M9, ME, or forthcoming M.
I admire Leica for filling the niche within a niche by producing a dedicated B&W machine. There really is no direct competition, always a nice position to hold. I won't be buying an M Monochrom myself, but I hope enough others will make the effort profitable for Leica.