I thought the consensus was that "flow" isn't actually all that great. If you're writing code while juggling multiple difficult concepts in your mind at once, your code will be difficult to follow. While in flow, you tend not to take the holistic, bird's eye view and so work harder, not smarter.
I haven’t considered this but it makes perfect sense. If time is critical or if you are understaffed, it becomes required, however. I’ve prided myself on my ability to get so much done in a solid 8 hour flow state in the past, when it was necessary, but now that I have a baby and work at a larger company, perhaps I can take some solace in the concept you shared.
I was decently productive while a "flow" practitioner but I am definitely more productive than that after abandoning it as a concept. It's much easier to pick up where I left off because code is structured that way.