I'm still a pretty junior member of the Gear Addicts Not-Quite-Anonymous. It is definitely the pursuit of the ideal kit for each situation that is the gateway to addiction.
However, I think buying gear as 'sets' is really the best way to go about it. When I started buying my gear a year ago, pre-BPL, I bought it piecemeal. I ended up think, well, gear X is a couple ounces more than gear Y, but it's cheaper/more comfortable/more multi-use, etc. Despite my goal of being lightweight, comprising on a couple ounce3s here and there ended up being a recipe for a 30lb base weight.
It's better to look at your set-up as a whole and decide where to sacrifice ounces for comfort/convenience/budget.
Now my baseweight is just under 12 lbs, and I can break the mythical 10lb barrier on non-bear cannister trips. And I've done it more economically than I did my first time around. (If you can count replacing 70% of your gear as 'economical')
Of course, it is easy to get carried away into 'compulsion.' LIke you said, info overload is largely responsible. My GG Gorilla is 23oz and can serve just as well on a 5 day trip as on an overnight . . . butbutbut, wouldn't it be great to just have a GG Murmur/MLD Revelation/Zpack for those short trips and save a pound? Yes, yes it would.
Also, ideally you'd have sleeping bags/quilts at 10 degree intervals(in both down and synthetic, naturally), right?
And you need different shelters depending on precip, bugs, site size and availability too.
I think there's a competiveness/challenge factor at work too. Competitiveness might not be the right word. But the same way a runner might challenge themselves to beat their best time every run, we have the urge to get lower by even half an oz each time we go out.