Google's stock and cash worth $6B is still better offer to than rising $100MM. Not only first is 60x more, but it is also the ultimate exit (done deal - wash your hands go to the bank to cash the check), versus "$100MM investment" is just a gas for a business to sustain it and move it forward.

So still you haven't convinced me that Mason was after the money. I think he obsessively believed in the idea, which to me (personally) has no merits from business perspective, therefore from the investor/stockholder perspective this is a nightmarish position to be in, but one has to agree Mason did build something good: he gave jobs to thousands unemployed and stimulated the recessed economy by providing platform for both businesses and customers to continue selling and buying.

edit: I don't believe Mason had a crystal ball to predict how future will look.