My view is that the broader SI's mission, the higher the bar should be for the overall impressiveness of the organization and team.

Can you describe a hypothetical organization and some examples of the impressive achievements it might have, which would pass the bar for handling mission M3? What is your estimate of the probability of such an organization coming into existence in the next five or ten years, if a large fraction of current SI donors were to put their money into donor-advised funds instead?