Well, that may be true. But then again, it sounds very similar to the argument against getting CNC tools at all.
Anyway, as someone else has suggested, the clear place to start is with systems for changing endmills and for changing toolheads. (I've been swapping spindle for plastic extruder to do 3d printing; another swap does flux & solder ... I'm getting some mileage out of the 3-axis robot).