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.
No single guy with no family to support has to fear failure though. It only becomes a fear once you have a wife and children to support - but that's why it's generally accepted that you first get financial stability before starting a family. Some people choose differently as people are always free to make terrible life choices - but they need to face the consequences then.
Even someone with a $1mil trust fund can make terrible enough choices to end up homeless.
