Whilst there is a trend for Companies to stop paying First Class tickets for the employee and his entourage (the wife and kids), the vast majority of major companies (British American Tobacco, Shell, PriceWaterhouseCoopers, SmithKline Beetcham etc.) still pay for their top directors to fly in First, whatever that (Minimal) cost to them is.
They always have, they will always will. Many of you will not understand it, some of you will, but at the corporate level, there are certain courtisies you are obliged to pay your top employees, which have worked with the company for considerable time (15years).
Paying them to fly in First is just ONE of many such perks top directors will get, and it is a reward for him/her for working his way up the ranks, and helping to make the company successful. That's how it works, and none of you would complain if it was paid for you, trust me.
Of course if you are one of the few that are paying yourself, then you have so much money that GBP6000 really is expendable multiple times. Note the following people I know have flown BA First: The Spice Girls, Lady Diana, Prince William, U2, Saudi princes (100's...), Lady Thatcher (she deserves First for life), Major, Blair etc.
All of the House of Lords are given First class on BA for life.
Not worth it for us, as we can't afford it, but damn worth it if you can.