I'm with you: the more replaceable and maneuverable the better. My focus is on freeing myself from as many logistic problems as possible while remaining tolerably comfortable. I've travelled with one bag in a few different countries, doing a few different kinds of things. Every trip I get a little better and carry a little less.
I am reminded of a TV show with two guests, one selling gadgets and the other a famous author. It was a disaster. The famous author kept saying "Why would anyone do that? You can just do blah instead and it's better for thus and such reasons."
But you can't readily make money off of blurting "This is a better method for X that takes less time and hassle and doesn't involve selling a gadget."
For me, packing light is about lack of hinderances. I carry two bags (!!!) because I find the organization to be easier, but I can still ride on the back of a hired scooter and walk 5-miles across town if needed. I'd rather just pack more underwear than spend time washing it in the bathroom sink.
If I am going to a big city I am inclined to leave with one bag but go shopping (I like socks and underwear from the Nike store) and fill up another bag to bring home.
I do that if it fits the purpose off the trip. I buy clothes during the trip if needed and that clothes are a nice memory of the trip when I wear them at home.
But quite often, my trip stars as a business trip, so I have to carry my laptop, or I want to do photography and I want to carry my camera and other equipment. For that I need a reasonable bag.
A lot of the expense comes from working out clothes that fit multiple needs and can be reworn multiple times without getting disgusting.
(I will say: a good bag is actually worth the money almost-regardless of how long your trip will be. Well designed straps and load arrangement make a substantial difference in how your back and shoulders will feel after carrying it through a trip. Matters less if you're doing 100% car travel, of course.)
I travel fairly light, and if Im down to one bag, its a durable Chrome "diplomat" messenger bag. It's a workhorse for me.
The only reason my setup is worth more than $200 (maybe $300) total is because of my glasses and contact lenses.
Mostly though i think it comes down to the old joke “everyone who spends more than me is wasting their money on exorbitant whatever and everyone who spends less than me is a cheapskate.”
https://jeremymaluf.com/onebag/
The list looks like the very definition of brittle to me. Every single item is from a different manufacturer, possibly rare, bespoke, or hard to find (a Japanese version of a highly technical jacket, underwear that even says it’s hard to buy in the description). We’re way beyond preferring wool socks here.