[neilv]

At the time Brin was a grad student, as you said, it was not-uncommon, but also not the norm, even in top departments.

The students who had programming experience from other than just their classes had a big advantage for systems work, compared to other students.

Though there were also a lot of students who had only undergrad programming experience, and had a lot more learning to do. Which is perfectly fine, so long as they know they have something to learn, and want to keep improving.

(The only annoying ones are those who treat professional and collaborative work like they're only trying to pass a class -- including the analog of only trying to get a homework assignment past the TA -- and think this is what everyone does. I suspect the ones I've seen would pass a leetcode CS101 interview just fine, because it's pretty similar metrics as getting into and passing CS classes.)