IBM didn't invent this scheme. Apple Lisa had Cmd+X,C,V. Early Mac apps switched to K,C,V but obviously they switched back at some point.

> IBM didn't invent this scheme.

Ctrl-X, Ctrl-C and Ctrl-V isn’t even part of the IBM CUA specification. CUA places the Cut command at Shift-Del, Copy on Ctrl-Insert, and Paste on Shift-Insert.

cmd-K for Cut? I don't ever remember that on the Mac.

I remember the lower left row on the US keyboard was always the first four operations from the nearly-ubiquitous Edit menu since day one.

    Z - Undo 
    X - Cut
    C - Copy
    V - Paste

Early apps frequently also had "Clear" in the Edit menu, which was like Cut except the cleared item didn't go into the system Clipboard