At the time, there were no alternative light sources fast enough for the task, so they just used what they had and learned how to escape the pitfalls. IMO, trying to adapt this technology is akin to making a 21st-century steamcar
Aren't tube mics 21st-century steamcars? Not cutting edge tech by any means, but we like how they sound so we still do it.
I'm interested in optotransmitters not because they're new (although I admittedly knew little about their history), but rather because I'm curious how they sound. I'm curious about what quirks they might imprint on the audio signal and how a light-based system would respond to saturation.