Oh come on, there's no way you can tell the difference in latency between a mouse of that era and a USB mouse today. Surely there's enough demand in the e-sports scene to lower input latency as much as possible?
This was of course done because the systems back then were so slow that they would be in danger of regularly dropping key presses or clicks otherwise, which would have turned people off these newfangled electronic typewriters. But the result was that the interactive experience with respect to latency was given great importance in the design of those systems, unlike today, when it is taken for granted that people will accept whatever laggy system they are given, and will just be directed towards a CPU upgrade if they complain about it.
A Windows 3.1 PC from that era, not so much :)