kelly, airlines that have those sorts of numbers are either expanding rapidly or are seeing massive staff turnover. Keep in mind that SQ also have significantly more number of Captains than do QF for the a given airframe. Perhaps that's what you mean by 'under employed'. The fact that we have S/Os whilst the likes of SQ and so on have F/Os who they treat like S/Os.
Time to command in QF as at beginning of 2009 was 14 years. Anyone who took longer was there by choice or lack of aptitude. Time to F/O was no longer than 5 years. Anyone who took longer was there by choice. I haven't looked at those numbers in the last 12 months, perhaps they've blown out a bit more now. That said, you know all this and so your figure of 20 years for command and 10 years to F/O is an outright distortion.