My reason for making the comparison was not to compare hours, but to show that someone in the office working 9 - 5 (give or take) with an hour for lunch and a couple of breaks during the day, who has been in the company for less than 5 years, can earn more than someone who has been here in a management role for the last 12 years and who has been very supportive of the company through many many very difficult and trying times!
Comparing any two roles is a red herring. The main reason being the supply of applicants for the cabin crew position is always going to be much greater than for any ground-based job. There has to be, therefore, a value attached to the appeal of a particular job. When you were a kid, you dreamed of being an Astronaut, Train Driver or Air Hostess - I'm pretty sure Call Centre Assistant, Office Cleaner or Sales Rep were pretty low on the childhood priorities list. And as long as there is a queue of applicants around the block, airlines know the remuneration package doesn't have to be pumped up. Looking it from the other side; if the money was the same for FSMs and SEP Instructors, which job would you prefer (or more precisely, which would have more job applicants?).
All positions (and their applications) find their market levels, which is why most of your later argument is irrelevant. Why do SEP instructors who've been at the company less time than an FSM get paid more? Because that's what the company needs to offer in order to attract & retrain enough staff to the job. There isn't a line on your wage slip for being with the company through 'trying times' or a 'supportive bonus', just like there isn't line-items like that on 99.9% of other peoples wage slips.
That said, what the cabin crew negotiation process is doing is attempting to re-adjust the value of crew to the company. Virgin have, up until now, used the attractiveness of the position combined with the attractiveness of the brand to keep the pay low - lets face it, most would rather be crew with Virgin Atlantic than LOT (no offence to LOT crew members, but Virgin has more of a cache).
Where I think this process has mis-stepped is that as long as the supply of applicants for Virgin crew remains (extraordinarily) high, any internal pressure for a major readjustment in salary will meet huge resistance from management. After all, every extra £100 per month paid to crew (roughly 5% increase, on average), will cost the company around £6m per year inc. National Insurance. Virgin reported a pre-tax profit of £41.6m last year, and that money has to pay shareholder dividends, invest in future growth and protect themselves against future costs such as fuel, etc. That means every £100 increase the crew get per month is costing around 15% of the companies profitability before tax. Not a decision they can take lightly, and not money they can simply take from the Virgin Group or Branson - business doesn't work like that, and if the company can't generate the cash to pay its own bills, it's unsustainable. Think about it - a huge queue of people wanting to work as cabin crew (even at current wages), and a minority (ok, 30% is a large minority) of incumbent staff wanting to push for an as-yet-unknown (but larger than 5%) increase.
So, the company is understandably very resistant to large additional (and ongoing) costs on the bottom line. That's why gradual changes upward, such as advocated by the pilots, would have been a much more sensible way of increasing the pay deal over time. The company would have had more time to absorb and adapt to the new costs.
There's been very emotional arguments about how hard crew work, and how much more they deserve. I don't doubt that they do; but the cold reality is that many people work hard and deserve better deals, but their employers simply can't afford it.