Mainly because the hit rate is so bloody terrible.

I interview programmers all the time, and hire about 1 in 50. And the ones I do hire are great, but I see some truly unacceptable people who have great CVs.

Or they've worked on something which is really interesting, and smart, and when you dig it turns out that they simply don't understand what the team did, they just 'did their bit'.

You _HAVE_ to trust your developers, even with code reviews, design reviews etc etc in place, or you end up doing all the work yourself.

Frankly, I think it's more a question of 'why don't they test the others harder?' ;)

The flip side, of course, is that I get interviewed HARD whenever I go for a job. And, frankly, I really enjoy it. Don't you? If you do this sort of thing because you have a passion for it, you'll probably get something out of the interview, not view it as pointless. In fact, I've turned down jobs because the interview was too cursory. I think it says a lot about a place, how high the barriers to entry are.