Every art I've seen teaches getting out of holds first because it is something a novice can do pretty easily with some understanding of technique.
I've also been hit in the balls during sparing matches a number of times. It's not the decisive hit many imagine. In fact, a strong solar plexis shot was much more effective in my personal experience.
A lot of "real world" martial arts teach about "disabling" shots that their practitioners never get to seriously try because they are, at least intended to be, truly crippling.
Yet that means that in the "real world", when assaulted, you are trying to do something you've never previously done in the same fashion.
For that reason, I think that "competition" based martial arts certainly can be at least as good for "real world" defense. The tactics used in MMA matches would work good in the real world - with the proviso to avoid fights and avoid the ground as much as possible.
If anyone wants to debate these issues in gruesome detail, look at http://bullshido.net . There's plenty of attitude there but it's a group of folks who've worked pretty hard sorting out bs from effective martial arts.