from my own personal experience I can tell that most of the time I prefer stackoverflow instead of man pages simply because I need to achieve one task and stackoverflow contains answer of how to do it, man pages can teach me how to do all sorts of a tasks, then I have to choose the right one from those that I have learned.
On top of that, to be able to use man page, I need to know command in the first place, while google will digest my broke english question and point me to the right stackoverflow answer most of the time.
I think it really depends.. I was at a job where it was like "Hey, these monthly md checks are causing IO issues let us disable them." So I read the man page for md and yeah... Let's not disable them.
This is an anecdote sure, but an important one. Not everyone needs to understand what's going on with everything but I can tell you the ones who seek out the information and really try to grok the systems are rare and can be well compensated for it.
Another anecdote: trying to use ZFS, and in particular de-dupe, without understanding it. De-dupe has its own trail of tears laid out from people who did not understand the memory requirements of it.
Hello, I'm Rapzid. I'm 30 years old, and I'm a man page reader. Sue me.
On top of that, to be able to use man page, I need to know command in the first place, while google will digest my broke english question and point me to the right stackoverflow answer most of the time.