I don't think we're headed for such an abrupt cliff as some make out, so essential medicines etc should carry on for a good while, but the change may be abrupt in many ways, such as the need to give up driving and get public transport. In rural areas, you may need to plan only one trip to the local village per week etc. Much like the old days. No more dropping Tarquin and FiFi off at the private school 20 miles away every day. Eating local. No tomatoes in December. You may find Rabbit stew on the menu again. You will have to rip up the driveway and patio you laid and put vegatable beds in, and grow soft fruits up the walls. If you are too old, get someone to do it now for you while labour is cheap. Raised beds are easy to work. If they are raised enough then they can be worked from a wheel chair.
Ok, essential medicines might carry on for a good while, but how long's a good while? I'd love to know, because, you know, my life depends on it. I'm not in a position to be optimistic about that sort of thing. The need to give up driving and get public transport; well, I can't drive and I'm not well enough to use public transport most of the time. I'm housebound, pretty much. My husband drives me to hospital appointments and the like but that's mostly it. We already plan everything around when we'd be driving somewhere unavoidably anyway, we eat as locally as is possible when your nearest local produce is a sixteen-mile round trip away but your nearest supermarket is within walking distance, we don't own our house and can't afford to buy one so really, what I'm saying is, most of the preparations and changes that people keep advising us to make are either things we already do to the best of our ability or things that we simply can't do. As for the raised beds being workable from a wheelchair - well sure, if you're in a wheelchair due to some kind of leg problem, but if you've got problems with your upper body then that's not so peachy. Disabled != wheelchair user, most of the time. Sorry if I'm coming across as snappish or harsh but it's pretty clear that you and many other people are talking from positions of able-bodied and financially-secure privilege. Those of us who object to that sort of thing aren't "putting obstacles in the way" or in any way unwilling to make changes - we're just very simply not in situations where much can be done.
So it might seem like we're being overly pessimistic, but in fact we're not. We're just stating the realities of our lives and not relying on the goodwill of people or community spirit to help us through, because the view from where we are is showing us that there's not a hell of a lot of that, but there's more than enough greed, malice, violence and prejudice even in our current BAU existence to have us very, very worried indeed.