yeah, that is a whole lot of what if's.
and it really depends on the time frame you are talking about.
10 years, sure. you probably can find all the parts you need to get a machine back up and running, or an emulator or an adapter to get data off something.
20 years, and now you will have some issues getting parts, adapters etc..
unless you keep the equipment sealed and powered off, there really is no guarantee it will fire up in any future run. sealed keeps any dust or bugs out of it. and humidity etc..
any more than that, and it is unlikely any new equipment will read it.
you look at flash drives as ubiquitous now. but floppy drives were too only 10 years ago, every computer came with at least the 3 inch floppies.
no computer comes with one today. 20 years ago, they all came with the 5 inch floppy drives too.
and yes some people keep working machines just to access this stuff. but it isn't cheap and it isn't easy.
moving to new media is more cost effective.