Compare to a nice grand piano: 1 meter of air ~3ms. (hammer travel after you bottom out the key - another 10ms? A MIDI keyboard doesn't know the velocity of the note (or send the note at all) until key travel is mostly done too.)

I have only 5 ms of ASIO buffering using my PC but I don't actually know how much actual key->sound latency; I do know that using headphones it's only slightly less immediate than a nice grand.

I think the low MIDI bit rate (31kbaud) also adds a little latency on chords.

It would be nice if keyboards in the future immediately sent a lower latency+precision keypress-initiated notice (before full key travel) so disk-based samplers can make ready for that note (and make any initial attack sound that's appropriate).