Casey's next stream [1] will probably be very entertaining! Back when the original drama unfold I could very much empathize with his frustration. Let's not forget they told him that what he was suggesting was the work of a PHD when any game developer worth his grain of salt could do that very trivially.
Devs over and underestimate effort all the time
Sure but in this case it was grossly over-estimated compared to the under-estimated side. Casey did the implementation [1] to prove the point and also made explanatory videos [2] of it.
[1] https://github.com/cmuratori/refterm [2] https://www.youtube.com/watch?v=hxM8QmyZXtg&t=1052s