That really was just the most absurd argument for Microsoft developers to engage in. It felt like a parody of the "optimisation is unnecessary because us developers are such Prima Donnas and simply toooooo expensive to lower ourselves to such levels" attitude that some people have.

He used a cache. A simple hashtable. That's it. He got an absurd speedup of something like hundreds of times faster.

What are developers smoking these days that they can't even envision ever doing something like this without undertaking a research program?

To this day people will debate this, as if there's a valid debate to be had!

"No, no, no, it's premature to optimise software that is... being released to a billion users in production."

"Casey is adding unnecessary complexity that will be hard to maintain... by using a fraction of the code Microsoft did to solve the same problem."

"It must be full of errors... well... other than the superior Unicode compliance."

"It's so much longer to develop high-performance code... the evidence is that it took Casey two weekends to write a nearly complete terminal emulator!"

Etc...

Look where we are today. Microsoft still steadfastly refuses to even look at Casey's solution, let alone adopt it wholesale. Years later there are still blog articles being written about the performance issues of the Windows Terminal.

PS: Notepad and Calculator got the same "treatment" and now struggle to keep up with key presses.