Living the lifestyle and maintaining it are not the same thing at all. Alexandria is living the 20th century with all those things, but they cannot maintain or sustain the 20th century. Parts are going to break or wear out.
Yes, I know. That's how it is
right now.
Clearly, however, you missed the brunt of this conversation. It's "what would happen if a cure was found and there was no longer any need to fear zombies, thus allowing humanity to go out and reclaim the world."
The vast, vast,
vast majority of the problems with maintaining equipment is the inability to freely go out and acquire whatever items they need, most of which (with the exception of perishable goods) is still readily available. And for the things that aren't, the infrastructure to acquire the raw materials (not that they would need to any time soon since tons and tons of it would be available) and process them are still out there.
I mean, hell, they shouldn't have to be worried about vehicles at all. They could go to any sales lot or, more likely, manufacturing plants and have their pick of pristine vehicles, many of which wouldn't even have gummed up engines because they would never have had oil or gasoline poured into them yet.
Semi-tractor trailers would still work or be repairable. So would aircraft and boats. So would long distance communications, most electronics, and all kinds of other things that would give them a HUGE boost in improving society in no time at all.
They're not actually in the Dark Ages. Or Colonial America. Or the Old West. They're just stuck with those levels of technology at the moment because of circumstances. Unlike the Dark Ages, Colonial America, or the Old West, all that "future tech" still exists and is readily available, as is the knowledge (either directly or indirectly through books and electronic media) to make use of it. They just need to be able to actually
do so without a still-occurring apocalypse stopping them.