1. Insulation is about the same with the exception of a few new synthetics.
Primaloft and climasheild, pretty much blows away the old stuff. Polarguard in its days was a s good as it gets, but very heavy. My 35dF snowlion polarguard bag weighed as much as my snowlion -40dF down bag.
There were 900 loft bags back in the 70's although very expensive. I have a 10" loft -40 snowlion bag from the 70s that weighs 4#. That would be considered UL even today for a true -40 bag. I used CCF pads back then too, also UL for the day.
What has changed IMO is more of a total minimalist approach, double duty gear use, IE gatewood cape and the like, quilts, lighter pads, much lighter tents, frameless packs made of lighter less durable materials less and less equipment, also insulating layers doubling as bag extenders etc etc. I did not know many people that backpacked that used a minimal shelter back then. A 5# tent was about as minimal as most wanted to get, and most people had a 5# bag and a 5#+ pack.
Now that is more like 5# total.
Quilts, bivys, UL tarps and frameless packs probably made the biggest impact.
Nylon cloth has changed a lot since my main backpacking days back in the late 70's and early 80s. The lightest weight nylons are about half the weight of the old stuff, lightest then I knew about was 1.9oz ripstop. Lightest coated was more like 2.4 oz.
DWR came along which is a godsend, Cuben, epic, momentum etc. Silnylon as opposed to coated etc.
That said everything everybody is doing now could have been done back then too with a slight gain in weight, like maybe 1-2 pounds more, with some ingenuity.
I think the ultimate UL hiking kit from the stone age was the one they found on the Iceman. Very interesting. The knowledge you could gain from traveling on foot with a human like that 5000 years ago would be awsome.
2. IMO there are some compromises in durability in the long term. 1oz ripstop has to be taken care of. Cuben even more. UL Packs too and you just cant throughthem around like a cordura pack.
Most people doing a through or a long hike now would probably buy a new pack for the trip. My old Kelty Cordura Alpine pack is 35 years old and still in good shape and I was rough on it over the years. I did rebuild it not too long ago. There is a price to pay for lightness in materials.
Compromises in safety I think varies more with skill level. A novice can get soaked in a $400 tent, while an Ex marine, might be bone dry with a bivy and a poncho. One thing I will say is that I think a strong dome freestanding tent is still more secure than a tarp in high winds. Again how a tarp is set up makes a big difference.
I think the hammock trend was an awsome idea. Funny back in the day you could not have given me a hammock. I was a 100% tent guy.
Off the ground with more comfort just makes too much sense. DIY is very cheap.
I used to hike with a 25-30# base weight, even way back when. That was on the light side. Some of my friends were 10-20# heavier, ouch. I allowed myself some luxuries I dont take now. As I look back that was heavy, but at the time, everything quality was just heavier.
2# cook kit with stove vs my 4 oz set now.
5# tent vs 2# tent now.
3.5# pack vs 1.5# pack now
That said after a while I ditched the stove and fuel just started cooking on a fire so that saved some weight back then.
These days IMO a 6# big 4 is a good goal for 3 season. 6# big 4, 6# for everthing else, 4# for 2L of h20, 10# of food for 5 days, puts you at 26#. Add 2-3# for winter depending on where you are.
Total weight of about what my base weight was back then.
Of course if you shop wrong, you can end up at 25# base weight now too, and pretty easily especially if you pack a lot of non essentials.
SUL gear can be expensive.
Your clothing selection looks good but fleece is heavy. You can change that out later.