Also, honestly, we didn't try hard enough before covid forced us to really invest in building a great remote experience. After covid started, we put all of YC's resources behind this, and built custom software and redesigned the whole batch experience to work well remotely. That's what it took.
It's also interesting to consider other areas where the cost-benefit ratio fluctuates depending on the level of effort - and that changes over time. For example, the US Air Force would probably say that drone aircraft are becoming important, but that the war in Afghanistan shows the US still needs aircraft with a pilot in the cockpit. However, if you gave the Air Force an ultimatum and said that in 12 months it had to fight a mock battle with only unmanned aircraft - and all officers would be demoted if they lost - then the US might develop a fighting capability far in excess of its current ability.