I would hazard a guess from the many youtube videos showing shallow approaches/low TCH that the issue isn't showboating (although it may be a factor). The issue is more likely a lack of faith in the performance figures resulting in landing short to get more runway to stop in. A feel good factor rather than wilful disobedience towards SOPs.
Why would pilot's have a lack of faith in the performance figures? Is it because they are so wildly conservative as to be almost meaningless? Or are they of little practical value even if they were more accurate; who comes to a complete stop on a runway ever during normal line operations? No-one unless it's a form of emergency.