I agree - many of the fundamentals of gear design haven't changed over the 30ish years I've been doing this. However, I do believe (at least in my own case) that gear has gotten lighter and more compact without sacrificing function.

Two examples: the Hubba/Carbon Reflex solo tent I use now is much lighter than the two-person tents they replaced. This is partly because, when I was using the two person tents, solo tents weren't available. My first tarp/groundcloth combo weighed about 3 pounds - about half what my tent weighed - but I gave up bug netting. Then, when silnylon tarps got relatively affordable, a silnylon tarp let me replace the groundcloth with a bivy sack that had mesh from head to waist. Then came the Hubba (and similar designs from other makers), and I could now have a comfortable solo tent for the same weight. (The Carbon Reflex was just a case of throwing money at a pound of weight savings because gear is my only vice, so I indulge myself.) But, the basic design of the Hubba is still a dome tent.

The second example is cook gear. For a long time, I carried a 2.0 and 1.5 liter pot set, a cup, and a spoon. Why? Because they hadn't invented cook-in pouches for freeze-dried food yet (nor had they figured out how to make the f/d spaghetti taste different from the f/d stroganoff.) So, I cooked in one pot and made tea water (and clean-up water) in the other. Eventually, when they became available, I replaced the two pots with a single 1.0 liter pot, and drank water with supper to eliminate the need for a tea pot or cup. (I could drink from the small pot if I wanted tea.) There, technique mostly reduced the weight and size of my kitchen (but a titanium kettle with handles eventually replaced the 1-liter pot and pot lifter, which was lighter and more convenient.)

The same things happened with a lot of other gear I carried, plus I replaced a lot of synthetic puffy clothing and sleeping bag with down items, which saved a small bit of weight and were a whole lot more compact. (Oddly, there wasn't a big change in weight or size when I moved to 800+ fill down. Again, that switch wasn't motivated by need, but merely because I wanted to.)

The result was that I no longer needed my big, heavy Dana Design Terraplane. I replaced it with a smaller pack that weighed 3 pounds, then experimented with 1 and 2 pound packs. Now I'm using a pack that weighs just under 4 pounds because that's the lightest pack I could find that had a suspension that, to my own way of thinking, was supportive enough to carry a 20 - 25 pound load comfortably. (And, on a winter trip I just did, a friend was carrying his old Dana Design Bridger pack - slightly larger than mine, but it weighed within a few ounces of mine, and was functionally the same design.)

The new gear is often lighter than comparable old gear, but not by as much as some would have you believe. I just looked over some old pack lists from my own arc of lightening my load from 35 to 20 pounds for a weekend. What I found was that simply changing my technique (simpler cooking, weeding out "nice-to-have" stuff, etc.), I took about 10 pounds out of my pack. My first round of gear replacement, just updating things without any obsessive push to reduce weight, saved 3 pounds. That got me to 22 pounds; I could easily live with that pack weight. The other 2 pounds were saved when I indulged my obsessive nature with the Carbon Reflex tent, NeoAir pad, and Hyperflow filter. That wasn't strictly necessary, but done purely because my hobby other than backpacking is playing with backpacking gear. (And, quite honestly, I'm still not convinced that the final 2 pounds will be my final gear choice - the items they replaced still, in many ways, are more convenient to use. Whether they are 2 pounds more convenient remains to be seen.)

So, yes, the more things change, the more they stay the same - the fact that a lot of my "cast-offs" are still being used by other folks is proof of that. But every once in a while, change can include some minor improvements.