Perhaps an easier solution than the author's don't-let-anyone-excel would be to de-stigmatize lower-talent positions. Tell your children they can be whatever they want, and then let them follow whatever they're good at. Even if it's plumbing or retail. Fundamentally, I don't think meritocracy is incompatible with mass happiness. (More technically, I believe there exists some value system in which pursuit of excellence is encouraged without associating a sense of shame to "lower" professions.)
> when someone proposes grand social engineering plans: What does it mean for a given person?
We have to be very careful here to view imbalances as potential indicators of underlying problems, and find and treat those problems rather than the symptoms. To use your example, we have to determine whether systematic pressures are keeping women from choosing CS, and correct those pressures, rather than adding new pressures to choose CS. This point gets made frequently around here, but the mistake is made often enough that it bears repeating: adding different counter-pressures that fix the statistics may mask the problem, but often also exacerbate the underlying issues.