The majority of the skills you learn in the ring can be used in the real world as well. Plenty of people have effectively used pretty much every sport art I can think of in self defense. Off the top of my head, I can think of videos I've seen of guys using Boxing, Wrestling, BJJ, Karate, and Taekwondo to successfully win a street fight or fend off an attacker.
And as much as I argue with people like
@Martial D and
@drop bear as to the efficacy of non-sport arts, it's impossible to deny the benefits you get from sparring and competition. The people who spar the best are usually those in sport arts, where they test their skills in pursuit of a tangible goal (victory in the sport) instead of a nebulous goal (preparedness for a street fight).
Even if you don't compete, sparring against competent opponents is important to learn how to manage distance and timing, how to set up your opponents, and how to use your techniques effectively. The biggest criticism of a lot of the "no-fluff" combatives styles that you're proposing are that they don't spar, or they only spar with people trained in the combatives school, where bad habits might fester (because nobody in the school knows how to take advantage of them).