I don’t believe the lack of remotely operating spectrographs is necessarily due mainly to the lack of suitable instruments. There are spectrographs such as the ALPY and DADOS which need no adjustment (In fact the SX spectrograph should not need adjustment in normal use with a suitable size camera really) and others like the Eshel which is capable of fully remote operation but you see very few operated this way. Remote operation of slit/fibre fed spectrographs is much tougher than imaging, particularly if you want to automatically acquire targets. (Andrew will be able to advise on that) Spectroscopy also needs a lot of telescope time which is expensive on rented telescopes.
Cheers
Robin