Whether you find this explanation plausible or not, the research generally agrees: too many choices result in less satisfaction with whatever you finally buy.

I've meant to comment on this research before...not as a critique of your point but just as a stream of consciousness:

The problem I have with using this to consciously decide not to do as much comparison shopping/research/whatever, is that, while I may be more satisfied with my purchase, I'm less satisfied with the way in which I made my decision. My gut feeling is that in terms of overall satisfaction, I'm more satisfied with the life where I do more research and comparison shopping than the life where I do less.

Of course, you do mention within reason, but I don't find that, for me, it's anywhere near apparent where the line between reasonable and not reasonable is at.

I find this general idea to apply to a lot of things that affect our happiness or satisfaction about a specific area. By acting or thinking in one way, we increase our satisfaction, but decrease it in another area. So, we have this example where I spend less time comparison shopping and I'm just happy to get my product and am very satisfied with it, but I'm less happy and satisfied with the way I chose it. Or another example is that my general day-to-day happiness would be greater if I believed in God since all my family and nearly everyone I've had a close relationship with are really religious, but I'd be less happy in...intellectual areas I'd guess you'd say?...because of the cognitive dissonance and my desire to improve my map.

ETA: Great post! Don't take this as any sort of criticism.