My argument is that the title of the article - and the conclusions of the study - don't really get to the heart of the psychology of choice. I would also argue that the author uses a straw-man to make his point - "People think they analyze everything a lot but they actually don't" - when in fact the gut-check you're going to get out of most people is that decisions are hard and we lose rationality very quickly.
This is the core argument of behavioral economics as a science - economics supposes rational actors while behavioral economics tests and evaluates the performance of irrational humans in economic situations. By contrast, the article is arguing that people are totally rational, it's just that we second-guess ourselves until we're stupid ("Your tenth sip of a juice will probably taste like the first").
Even then, the model is dumb. Your tenth sip of juice won't taste like your first because taste is a chemical process and taste receptors run out of supply. Your evaluation of your employee is going to be context-sensitive depending on what's going on at work. The authors are arguing that you should make a snap decision and stick with it while also being aware that other people make snap decisions and stick with it when in fact, the process of decision-making is a rational approach based on a non-obvious evaluation tree.
I think they wanted to say something unsupported by evidence so they designed a flawed study that would give them the result they wanted. Do people overestimate their decision-making process? No, people don't understand their decision making process and this study doesn't help.
This stuff is crazy interesting to me because when you consider the world is run by economists - and when you consider that they're demonstrably wrong about what drives economics - you see an opportunity for some insight into the world. And to me, your article boils down to "stop thinking so much" which misses the point.