However, I am far from the best interlocutor of such an argument, since my own bias interferes with accepting the necessary premises even where aware of them.

Yet Obamas meaning is crystal clear from statements like "when we succeed, we succeed because of our individual initiative, but also because we do things together" and "We rise or fall together as one nation and as one people, and that’s the reason I’m running for President -- because I still believe in that idea. You’re not on your own, we’re in this together" make his meaning crystal clear though: We (not I) DID build this. He credits individuals—ALL of them, including those with their names on company letterhead, but everyone else involved, too, invariably including some degree of government, past or present.