PL specialists are also pretty
good generalists.
It has also been my experience that people with a PL / compiler
background are often great generalists. At Google I can think of at
least the following:
Jeff Dean, Fergus Henderson, Ken Thompson, Rob Pike, Ben Gomes, David
Stoutamire, David Bailey, Urs Hoelzle, Hal Abelson, Martin Abadi,
Peter Norvig, Sanjay Ghemawat.
There are more but can't think
of them off the top of my head. Chris Lattner is a non-Google example.
(As an aside, I see a similar phenomenon -- albeit at a much lower level of ability -- in my undergratuate students, and I've supervised a large number: top students almost always do well in / and have enjoyed their compilers course.)
Why would that be the case? I can offer 3 hypotheses for discussion.
1. PL / compiler stuff is so trivial that everybody can be good at it.
2. PL / compiler stuff is so difficult that only the smartest can be
good at it.
3. PL / compiler stuff forces you to think deeply about the most
important tools in programming, namely the CPU and programming
languages, and the bridge between them (the compiler).
I'm inclined to go for (3).