I had to constantly remind myself, when my college friends were going off to do startups that they wouldn't be sleeping under a bridge if they failed.

Even something as simple as a supportive family is a huge leg up compared to those who don't have it.

“Even something as simple as a supportive family“

That’s a strange wording, isn’t a supportive family widely known to be an absolutely huge benefit?

I think the implication is that, as opposed to starting a romantic relationship with someone who can support you or a side hustle or etc., having a supportive family is much more passive (and somewhat a roll of the dice, but generally speaking if you were lucky/privileged enough to be born into a family who can emotionally and/or financially support you, there probably isn't much labor/effort you had to put into to make it that way).

It's for sure a huge benefit; I think their point is that it's a huge benefit that doesn't require effort (just chance, or maintenance of good communication/relationship).

Everyone in silicon valley is familiar with founders that got seed money or connections from friends and family. My point is that even having a safe place to sleep isn't assured for some people, and folks should remember that when they pat themselves on the back for 'taking risks' founding a startup. Some people would be taking much larger risks than others.

What do you call a girl on the arm of a harmonica player?

A tattoo.