Dissappear? No, of course not
Fall out of repair, and be unable to be repaired effectively without tools, resources, or knowledge that are no longer accessible?
Abso-fucking-lutely
Take a deep sea oil rig. How long do you think it’ll be operational without maintenance with all that sea water? After not too long you won’t be able to repair the damage without serious industrial capabilities, and that’s assuming you even know how to fix it.
Really even as relatively little as a few decades of total chaos and disorganization would be enough to make crawling back really hard. A century and more and it really could be impossible, or at least improbable - especially given that the humanity that comes out of the other end of the crisis is the same one that got us into it. So the remaining pieces of major valuable infrastructure left will probably get wrecked as the survivors fight over them
Yeah, remember the reaction when that one post got popular about lemmy being boring for anyone that wasn’t a SWE/Linux user?
People got so pissed off, one of the top posts on lemmy that day was something to the affect of “fuck you, we’re not obligated to post things you like”. Which, yeah, you’re not - but you also can’t blame people for losing interest in your platform when you only have active discussion on one or two relatively niche topics.
The fact is that Lemmy is garbage for discussing hobbys or interests outside of a few niche areas. On reddit my feed was filled with woodworking, 3d printing, Astronomy, and other topics that get very little traffic on lemmy.
My lemmy feed is mostly politics, then SWE stuff, then memes