Appropriately I was off hiking in the mountains all weekend. A few thoughts as always on the comments.
Metallurgy. This will not be an issue post collapse for at least 500-1000 years. Why because the worlds is awash in mountains of dozens of different types of steel. Scavenging and cannibalizing will dominate for hundreds of years. Think how much metal of different kinds just sit in an auto junk yard. If it rusts into a pile that is also your source of concentrated iron ore. One is going to need piles of coal or charcoal to burn for forging though.
Skills. I hand make weapons (my chosen field is edged weapons - knifes and short swords). The quality I can make if taken care of properly will last hundreds of years. The top quality firearms made today will also last hundreds of years. Even when frequently used. A top quality automatic 9mm or 45 cal is capable of being fired 20,000 times before it is worn out. I still have my grandfathers WWI army rifle and it is perfectly usable and it is 98 years old. The volume of ammunition existing today would last a very long time. And we are making billions of rounds every year. Reforging or reworking existing metal is not difficult and we will be able to make almost anything for quite some time. In a friend of mine's knife shop there is a milling machine and a precision grinder that were built before there was electric power to run them (they were belt driven from steam engines). They are accurate by a skilled operator to better than 1/ 10,000 of an inch. One can easily use them to build any small arms parts needed from that huge pile of metal laying around.
Every farmer and village is going to be armed to the teeth and raiders will not last long. War lords will however and the farmers will align with them and create feudal societal structures for self protection. My ancestors (And likely yours as well) were all farmers when they were not soldiers. Fighting was their 2nd job and no one is going to easily take anything from them.
We are not going back to the hunter-gatherer stage except maybe in the far north or islands in the Pacific. There are not going to be any animals left to hunt. We are going back to, IMHO, to a feudal agrarian society which will have many trappings of the modern world like our weapons and medium tech knowledge. Much of medicine will survive as long as you do not depend on the very high tech stuff. A reasonable large manor will be able to produce penicillin for instance.
While I don't agree with all of John Michael Geer's thinking along these lines I do agree in general with his stair step societal decline which takes place over hundreds of years. We will lose a lot of capability at the crash and in the few decades thereafter. From that time on it will be gradually down overall until we reach a stabilization point. Depending on when the collapse happens and how far the initial fall is determines how the following years play out. It is quite probable that we eventually stabilize at a low industrial level with trappings of medium technology. If collapse is very deep very fast we could go much lower to the medieval level but still with a lot of modern knowledge and some modern technology. But where ever the bottom turns out to be it will not be reached for hundreds of years most likely as we will be living off the detritus of our current world. The big issue is total global population and how long it takes to get it down far enough that the climate and eco-systems stabilize. With only a billion people left we can have a pretty capable level of technology (not sustainable but able to exist for millennia). But we have to get down to those kinds of numbers quickly to achieve that. If we run the table trying to keep this disaster afloat we will turn the Earth into a cinder and how many the Earth will be able to support and their level of technology will be greatly diminished.
SATire:
Such things like a collapse are high risk and low gain tasks. By definition a collapse is not controlable. Therefore, you can not expect to reach any goal by it. The revolutionary romantic of todays talking will change into an ugly situation for everybody once the fiction gets closer to reality. I can see no reason to go for the collapse. For me it looks like "bla bla" of radical poeple: who is the most radical in the room is going to win the show. I can not see how such things could help us. Things that help are e.g. Amish BAU, green BAU and any other way of life we learned in human history which would not depend on holes in the ground and CO2 in the air. I think there is realy a lot of work to do for anybody of us and there is no valid excuse to start the work.
I do not agree with your high risk low gain characterization. Collapse is coming either way so that is not part of the calculation. The choice is early or late in time. Later collapse is a bigger collapse so that is worse I believe. Which delivers the best result? I say it is early so that is high gain and later is low gain.
Yes you can reach a goal by it. Given that the longer we go before collapse the more resources we consume and the more critical damage we do to the eco-system, it matters tremendously when that collapse happens. If collapse happens in 2050 then we have 36 more years of destroying resources, raising carbon levels, higher eventual levels of equilibrium temperatures and sea level, a crash that happens from 9+ billion vice 7+ billions (vastly more death and suffering), etc. And will almost certainly result post collapse in a lower level of survival and technology than if we triggered collapse sooner. The goal is to have more resources and a less hostile environment with an early collapse. Is there any argument that an early collapse would not satisfy that goal? Developing skills for that feudal society is sound also, but not sufficient.
By choosing to drag things out as long as possible, as you advocate, and as I am equally convinced is exactly what we are going to do, is to deliberately choose the path that leads to MORE suffering (though someone else's instead of ours - a typical response) not less suffering. One may as well acknowledge that reality if that is one's choice.
How is it more 'radical' for one person to want to choose a path that results in less total suffering while the person claiming not to be a 'radical' is choosing a path which results in more suffering?