That modem analogy doesnt work, because what you are talking about is bandwidth, which is totally irrevelant. It would be like comparing a keyboard plugging in usb 1.1/2.0 to usb 3.0. The bandwidth is not the bottleneck when it comes to response time.
What RK does is this : NO DELAY - The signal is read in realtime at the press of a button.
Which means when you press a button, the key is registered. It is not a human limit at all. This is 1ms key response time which is much faster than 20/25ms response time.
That Takahashi Meijin analogy doesnt work either, because you are talking about someone who can press as many keys as possible in a second to key response time. The response time is irrevelant to the amount of key someone presses in a second. What you are comparing to would be closer to KRO/debounce time. Besides, it doesnt work that way... Someone who presses 16 keys per second doesnt mean he presses a key every 62.5ms . He could be pressing 2 simultaneously and have his next 2 keys with a 100ms delay between them or something like that.
There are vastly bigger sources of latency to eliminate. In the case of computer input, it's on the human side of things.
And all latency that can be eliminated should be eliminated, it doesnt matter the source. Human has nothing to do with the amount of time it takes for the key to register after being pressed down.
You press a key, it registers at 1 ms or you press a key and it takes 20x longer to register. I will take the 1ms anytime. Its faster. You dont have to notice it - its there... It will register at 1ms whether you notice it or not.
Now... The confusing part - Cherry MX website state that keys are registered with a 1ms delay. Which should technically mean between the time it takes to register the key after its being pressed down. I mean, they did go from digital to analog signal processing.
But other websites claim they just reduced debounce time to 1ms... Which does not mean keys are actually registering faster.
Although marketing is strong these days, I prefer the Cherry MX explanation, which would most likely cause the initial pulse to register without additional delay by using analog over digital scanning.