I think a lot of this makes sense when you realize that the typical tech company isn't really trying to do something that's very difficult. The average internet company is chasing some gimmicky take on social marketing or a trivial mobile fad etc and your ability to succeed in that kind of environment is going to depend more on your ability to work corporate politics than your technical skills, unless you're absolutely incompetent.
This is much less the case at companies that are tackling hard problems though.
I agree with much of what you're saying, but I don't think the "typical" tech company is anything close to the HN stereotype web start-up. Most tech companies -- and almost all successful tech companies -- are not just implementing some obvious, trivial web/social/mobile service and hoping to luck out on a quick acquisition.
That's probably true. I think what I'm saying holds to a large degree within companies too. For instance, you're probably going to have fewer opportunities to distinguish yourself by ability if you're administering mail servers at Intel than you are if you're doing chip design.
This is much less the case at companies that are tackling hard problems though.