I see what you're saying about the value of the prototype. How would you account for whatever risk the non-technical cofounder took on to build it? Risk has to coordinate with value added though, so if a prototype didn't really generate any new value, it's worthless. Perhaps there is some value in "lessons learned" from messing up the initial prototype, but maybe future investors/partners shouldn't be penalized for them.

You're right about not accounting for business skills the technical cofounder brings to the table. I need to state that somewhere. Great point.