There are too many examples already where electronic data is unreadable because the hardware to read it no longer exists
If there are "too many examples" then how come nobody is able to site a single example? Go ahead: name a single media that is unreadable today.
how many have the means to read 8" floppies today?
Everyone. The drives are available on EBay, and there are business where you can mail an 8" floppy, (or a tape, or whatever) and get the contents back on an SD card or CD-R, or just emailed back to you. To the best of my knowledge, no hardware format has ever become unreadable, and these old formats were far less ubiquitous than modern media, like CDROMs or SD cards.