But this is almost unbelievable that nobody yet created a logic board
with an FPGA/whatever which converts the signals/creates the missing
signals. May be too much old drives are still available ...
Indeed, old drives are still plentiful and cheap, for the most part.
Though not everywhere in the world, of course. The function necessary
would be to duplicate the analog board that currently lives inside the
Disk II drive.
[...]
But the need/incentive to go from Disk II interface to some other kind
of floppy drive simply hasn't arisen.