Is the existence of a trust fund actually relevant for the story? Whether there was one or not, as you already said, Gates didn't have to fear failure. I doubt the family would have let him live in poverty on the street if he had failed. I don't think it changes the narrative. But it's bad that - if you are right - the wrong story is out there because it gives a convenient escape to get sidetracked and be able to ignore the actual message.