>The engineer who opens a pull request, taps a colleague on the shoulder immediately, twiddles their thumbs for half an hour, and then revises and merges immediately has done the same amount of work, but much faster.

Completely agree. Unfortunately corporate environments tend to reward people that are "busy" instead of productive. I've been in many environments where I had to wait for a lot of people that were busy to gather requirements, slowing me down immensely. How do you deal with that?