IIRC data correlations from The National Longitudinal Study of Adolescent Health (with data sets based on ~15,000 adolescents) showed that those who are rated very unattractive averaged an IQ of 94.2 where as those rated very attractive averaged 100.7. Interestingly Male IQ's differed by 8 points, where as women's differed by an average of 6 points.
The fact is there are conditions, specifically Down's, that have an effect on both physical development and mental development.
I think saying attractive women are disproportionately hired and promoted is misleading, because we're now ignoring actual social factors at work rather than simply attractiveness.
If we're going to look at stereotypes then lets look at why female CEO's exhibit male-typical personality traits, and associate that with the known tendency of employers to hire people they can relate to. Or the "catty" female stereotype. Or numerous other stereotypes that aren't actually contrary to evidence, because evidence says hiring women for attractiveness is exactly what employers should be doing, because on average it works.
The question the original article begs to question is "are employers hiring less skilled attractive employees over more skilled unattractive employees" and the article didn't answer it beyond pandering to the "ditzy blonde" stereotype of women in the office.
I think things like second generation college students perform better and that education may not cross gender gaps as effectively, correlated with less women being second generation college graduates is going to have a bigger impact on the supply of competent women into the higher echelons of a work force than men hiring with their dicks.
Today women tend to outnumber men in colleges, which in 40 years time might mean that this wave of second/third generation female graduates might also be dominating our CEO seats.
I'm pandering to a half dozen stereotypes here for the exact reason that we presently know nothing on why we have fewer females in top positions.