In the interview though, he says it started when he bought web cams for his daughters but there was no Linux support.

But then he realized that a lot of the code was shareable, so he generalized it to 235 cameras.

You could call the difference between making 2 drivers work and 235 "altruism". Or you could just call it "doing it a good job". Most people have the desire to do a good job.

I frequently do the same thing... I call it cleaning up dirty hacks, and learning the essence of a problem. Not necessarily altruism, but I won't object if anyone calls it that.

Never underestimate the benefit of people showing off. Otherwise Mozart would have retired at 12 and become a music teacher