sub-microsecond triggering should be doable with a level-2 cut-through switch and an ethernet broadcast no? I admit that ethernet is not really designed for that as the Phy is then the latency bottleneck.
GPIB GET works by first configuring a subset of bus devices as listeners and then sending a single-byte message (it’s an 8 bit bus, so one bus cycle) with the ATN line asserted. It’s intrinsically low latency without any special effort.
Whether that makes it worthwhile to put GPIB on a new instrument in 2025 is a different question. I’m only addressing “what does GPIB give you”?