I have a different bag with my camping gear (tent, stove entrenching tool.)
But for the most part I'm not going to camp; moving toward home, to a friends or a shelter.

And with this one assumption I can eliminate 2/3 of the weight.

Many commercial kits have a weird assortment of things, too many of some
(hardhat?) and some not near enough (food, batteries, raingear)

Yes.

It's obviously going to depend on factors like terrain, climate, and how long you're expecting to be getting home or bugging out. For a short-term (72 hours or less) kit I'd expect "real" shelter items to be a huge amount of weight and space compared to anything else other than perhaps water. What's appropriate for me to "get home" in an urban/suburban setting is going to be very different than for someone who might need to hike fifty miles through the mountains.

I think that having a "non camping GHB/BOB" is a good idea. I think I'd term this as a "go bag" or even a "ditch bag".

What's in it will depend a lot of your situation. How far are you from home? What's the weather like? How fit are you? How populated is the area in which you live? How resourceful are you?

I don't have any answers, but let me put together an example.

If a person who has the primary concern of getting home without a vehicle regularly runs half marathons, lives outside of a major city (no mass transit, small towns) in the northeast US, and works fewer than 6 miles from home, 8 months out of the year, a jacket and sneakers are probably all that person really needs to get home.

Again, this is just an example.

Similarly, there are probably people who could walk out into just about anything with a leatherman, a lighter, a good set of clothes (for the weather) and the gift of gab and end up doing just fine wherever life takes them.

Situations vary considerably and obviously,one size does not fit all. At various times, I have been anywhere from 100 yards to 20 miles from my workplace.

For sure, just about everyone will need comfortable shoes and a filled canteen

Carry what is appropriate for the situation, but your basic priorities remain the same. How you satisfy those priorities may change.

After a recent vacation I realized how much "stuff" is protection from the elements;
sun: hat, glasses and screen, rain coat, long pants for weeds, etc.

Non camping GHB/BOBs are more useful than we think. It's not always a case of regional SHTF scenario where we run home. Sometimes it is a personal SHTF where we may need to do things in very limiting situations.

Last few weeks I have been disabled by osteoarthritis in one knee, and my view of everything is changed. Navigating thru the house became as hard as navigating thru dense jungle; every step was slow and painful. What I easily grabbed from here or there around the house, needed several painful steps, to the extent I even changed my mind and quit trying. Relief came when the wife brought me the "office bag"( a bag full of office stuff, a mobile office of sorts), and the "companion bag" which always comes with me (not a GHB, but sort of EDC/utility bag)

This is not the same as "get home" scenario, but trust me, when your movement is limited, you will appreciate a well-planned companion bag/GHB/EDC bag. Although wife and kids were very helpful, but they just didn't know everything I needed when I needed it. From flashlight to nail clipper, this bag beside my bed was of great help because it had exactly what I needed, of the type and specs that I needed, for the job that I needed; since I was the one who chose the stuff in it.

A camp-less companion bag is very valuable for so many unexpected scenarios.

Well said, Chisel. I took last week off for some personal travel, and deliberately left my laptop at home...but I took my laptop bag, because it had all the other things I would need for the trip conveniently organized.

I'm in a similar situation with an arthritic hip, leading to a very gimpy sore leg. For me, that leads to a classification of "hard core EDC", (phone, wallet, multitool, key ring, bandanna) and "nice to have" items (water bottle, snacks, notebook and pen, FAK).

This usually goes in my nicer day pack, which actually has plenty of room for most of the usual camp items which can be inserted if outdoor activities are contemplated.

Very useful. I follow the layered approach and have a non/camping setup.

Think about all the things you need daily, from medicines to vitamins, deodorant, toothbrush, clean underwear and socks, etc. make a place for those and a rotation schedule. I read a lot of info from frequent travelers on how to keep things pre-packed and ready to go and applied to this layer.