I would buy a machine that makes new floppy disk media if it existed, and not because of any economical argument.
I would buy a machine that makes new laserdiscs if it existed, and not because of any economical argument.
... aluminized paper for electric arc printers
... wax film thermal print head ribbon
... a re-inker for cloth typewriter ribbon (at least this one is straightforward to design and build myself some day)
... extra wide cloth matrix printer ribbon with 4 colors
... 1.9mm magnetic tape for exatron wafers
A record cutter has way more potential audience than any of those. They will sell every one they can even manage to make.