IMHO the mindset is indeed different. The competitor goal is to WIN. The self defense goal is to BE SAFE. Winning (a fight) does not guarantee safety. Moreover, focusing on
winning instead of
escaping may lead to very unsafe outcomes.
Notice how many of Abernethy's drills end with him backing away from the "opponent". Punch, sweep, escape. NOT "finish him off", "take full mount" or "GnP". I've personally seen streetfights where "winning" guys in full mount were brutally KOd by the downed guy's buddy. ESCAPE is the self-dense goal, so whether you need to strike or not, that's where your mind should be at all times.
Here's a very "mindset-focused" piece on self-defense that I highly recommend:
http://www.wimsblog.com/2013/04/self-defense-tips-for-men/
Note that there's no FIGHTING TIPS in there. Why? Because fighting should be avoided if you want to be SAFE. Accepting this simple truth is essential.