Why do people spend £5000 for a business class flight where an economy will cost them £800. Because they choose too.
Not quite.
The purpose of business class is so the “employer” can be suitably rested on the flight, that they can get straight to work when they land.
The cost of the flight is offset against the cost of them not working.
A friend of mine recently moved out to Florida to work in the upper tiers of a cruise ship company – [for example] he will work (in Florida) on a Monday, fly Monday night, have a meeting in London 9am on Tuesday, fly back Tuesday afternoon, and be in the office on Wednesday morning.