Your modulator/demodulator went from being a simple transceiver chip to a whole laser module. Fiber optics handle cuts and “wire” damage poorly compared to copper. It isn’t as easy repair or maintain, even a simple continuity test now requires specialized equipment and you can’t probe but rather need to plug in at each point, ok but what if your issue is the connector? Fiber is always point A to point B, which doesn’t mean you can’t HUB or DaisyChain or STAR, but isn’t as easy as some copper systems like CAN, FLEX, and maybe others that can just splice together. Double any complexity because these systems are redundantly run.
I’m not sure how big an issue is with EMI. Nor do I know the bandwidth. It’s just that the most complex vehicles today, they’re most well under 800kbps for the chassis bus (assuming some vehicle at 1Mpbs and 80% load). Not sure if anyone is actually making use of production 4-8Mbps systems yet. So I assume that rugged Ethernet for data haul and CAN for sensors would work as well as it is now for jets.
They must be doing some serious data transfers I don’t understand.