Earlier quoted context omitted.
“Ultralight” backpacking favors skills rather than gear. Folks have done entire 3k mile thru hikes with 5lbs of gear. The main way you get that low is simply by not taking much with you. You carry only the essentials. I don’t know if this is what the parent poster was referring to but it’s what my mind went to.
5lbs of gear is 5lbs of gear. And this seems like an extreme example - have you done 3k mile thru hikes on 5lbs of gear? What does that look like?
I used a summer sleeping bag that was 14 oz after I cut the zipper off (Marmot Pounder, which I wish they still made).
I had a "blue foam" sleeping pad that was cut down to size, which is extremely cheap and light. I now opt for much heavier sleeping pads. When cowboy camping along the AT you do not need much of a sleeping pad because you'll likely be on top of leaves, but on a shelter floor it's not enough.
For shelter, I just had a 6 oz sil tarp for when an AT shelter was full and I expected rain. I set up the tarp exactly once, and it didn't rain anyways.
My spare clothes were a spare pair of socks, a fleece shirt, fleece gloves, and a fleece beanie. None of those were expensive. I had a $0.99 plastic poncho for rain gear.
I did not cook, so no cooking gear. I had a digital camera which I barely used. And then just small stuff like toothbrush, water treatment drops, etc.
My base pack weight was like 6 lbs and change, and I had a tarp and camera I wasn't really using.
So, yeah, you can hike extremely light and not spend a lot of money. It depends on what trip you are doing. I started very late in the season, so the weather was warmer and shelters were not full.