I classify "overcommitted" as a form of getthereitis. When things start to go wrong, it's easy to fall into "I want to get on the ground now". That fear prevents you from wanting to fly more, so you continue on.
Good review.
PS> I also experienced the high DA inability to descend situation on my recent flight out west in my Mooney. Very similar to what he described, but I was on a very long approach and it was not an issue for me in the end, but I definitely thought to myself "I'm using everything in my toolbox and still barely descending". He is the first person I've ever heard describe the phenomenon. In my situation I was descending from 12,000 down to an airport with a DA of 4500.