Anyone with one or two engineering classes can easily spot that you don't know the first thing about engineering including the corner stone of cost effectiveness. You prove this every time you open your mouth about lunar based asteroid detection when the vast majority of those actually working in the field propose far less expensive options to meet the same goal and you turn a deaf ear to every technical challenge to your position.

Zubrin is an aerospace engineer, Musk is not. Musk has the money to hire enough aerospace engineers and buy enough materials to build his own rockest while Zubrin doesn't. That is the key difference between them. NASA adapted Zubrin's Mars plan because he out thought a slew of NASA engineers. They modified his plan with his involvement based on different sets of risk tolerances not the infeasibility of his plan.

The differences have been discussed many times without any relevent engineering comment from you. If you want to have any credibility stop acting like you are an expert on topics you know next to nothing about. Based on the majority of your posts I suspect you have little science training as well as 0 engineering training.

Regards,
Mark