My experience with people trying to replace a keyboard is that they forget about my use cases and then they're surprised that their solution won't work for me. For example:

1. I'm in a team video conference and while we are discussing what needs to be done, I'm taking notes of my thoughts on what others said.

2. I'm working as a cashier and the scanner sometimes fails to recognize the barcode so I need to manually select the correct product.

Now let's look at common replacements:

A. Voice interface? Can't work. I would NOT want to shout my private notes into a team video call. The entire point of me writing them down is that they are meant for me, not for everyone.

B. Touch screen? Can't work. I can type without looking at the keyboard because I can feel the keys. Blindly typing on a touch screen, on the other hand, provides no feedback to guide me. Also, I have waited for cashiers suffering through image-heavy touch interfaces often enough to know that it's easily 100x slower than a numpad.

C. Pencil? Drawing tablet? Works badly because the computer will need to use AI to interpret what I meant. If I put in some effort to improve my handwriting, this might become workable for call notes. For the cashier, the pen sounds like one more thing that'll get lost or stuck or dirty. (Some clients are clumsy, that's why cashiers sometimes have rubber covers on the numpad.)

I believe everyone who wants to "replace" the usual computer interface should look into military aircrafts first. HOTAS. "hands on throttle-and-stick". That's what you need for people to react fast and reliably do the right thing. As many tactile buttons as you can reach without significantly moving your hands. And a keyboard already gets pretty close to that ideal...