8 inch drives never made it to consumer use. They were only for the big computers of the day. Things like newspaper typesetting machines.
No it's your memory that's failing. As other people have pointed out, one of the TRS-80s had 8" floppy drives. The first computer I ever used was an Ohio Scientific something-or-other - 6502-based, with 48k of memory and dual 8" floppy drives. These computers were at my high school, and they weren't multi-tasking systems, so they couldn't have cost that much.