Re: I'm surprised
There are actually several physical emulators on the market which does that, but most hardware has the floppy disc soldered to the board, so it requires physical disassembly and replacement instead of just being unplugged as it is in a PC.
I did it to a really old system we had, but I was only really willing to do it because I had two of those complete boards spare from buying up other systems which other people had finished using. (Manufacturer support ended ~2007 IIRC)
My design level modifications to the system freaked out the engineers who used to support it a bit. (they still supported systems around it, but not that particular bit of equipment (due to constantly incrementing yearly support charges it was cheaper to buy 3x spares of everything so we had complete spare systems ready to go.) Their managing director had actually been on the design team and came to look at in person at what i'd done to it.
(Once you had a USB interface then if your willing to play then you could have a PC next to the device and directly push things to the "floppy disc" from that computer, which meant that the device which predated modern networking was defacto networked instead of floppy fed)
I found it quite funny that he took plenty of photos, asked loads of questions and a couple of demos, but the closest he came was about half a meter from the equipment, obviously wanting zero risk that he'd end up being asked to have anything to do with supporting it!