Some of that isn't the text editors fault. With the C64 the keystroke may be on the screen before it out of the USB stack on a modern computer. That is even before you start to consider the latency in the video stack. As John Carmack once noted: "I can send an IP packet to Europe faster than I can send a pixel to the screen. How f’d up is that?" --
https://twitter.com/id_aa_carmack/status/193480622533120001