The line "Then the firm's programmers hit their computers, with no other meetings or distractions for the rest of the day," is absolute rubbish. Most teams have at least an Iteration Planning Meeting and a Retrospective each week, as well as generally a team-specific standup the majority of (if not all) days. As well, there are of course manager 1 on 1s, the rare company meeting, and ad-hoc meetings as a project sees fit. Sorry, I just had to comment because the quoted line is absurd.
Edit: and the line about leaving work 6pm sharp is just as ridiculous. In the consulting side it tends to be true that your workday is over at 6 PM, but you're not going to get shoved into an elevator before you finish your commit message at 6:01. The limit is there so you don't overwork and so that the client companies know they can't push their consultants arbitrarily late.