What about all the hops your signal has to take to make the round trip? Couldn’t those be optimized or sped up? Is copper latency really equivalent to fiber?
Notwithstanding differences between specific types of cables and transceivers, yes, the rule of thumb is that they're roughly equivalent. The big advantages with fiber mostly come with being physically smaller for a given bandwidth (e.g. more bandwidth per square inch of conduit cross-section, more bandwidth per cable weight for vertical or suspended runs) and needing less active equipment between any two points in the network (e.g. PON, long-haul single-mode runs).
