Your logic is correct sir.
We still don't have any concrete details on the new M3/M4's performance, it's all speculation at this point. The 997, while a great car, may not be a suitable daily driver in the long run. The M3/M4 will seat 4 comfortably and will be a better everyday car as opposed to the 997. It's no slouch either.
It may be just you at the moment, but when you do find that special lady it might be a nice gesture of faith to be driving around in a luxury sports car that seats a family as opposed to a full on sports car for speed nuts