Earlier quoted context omitted.
And of course if someone doesn't stay later it means they're not dedicated to the product, so obviously aren't suitable for promotion, salary increases, etc.
No, actually, that wasn't usually how it worked. It was all about performance rather than time spent on-site. If you could get done in 4 hours what took me 8, you would be just as eligible for any promotions as I. Probably more-so, however, since you'd probably have worked 8 hours anyway and gotten twice as much done. ;)
i.e. if someone was equally productive (or even 25% more productive), but still produced less than you purely because they worked the scheduled hours, than they'd be less likely to get promotions, etc. ?