Upvote:4
There are many ways to get a business class tickets so statistics will be hard to come buy.
You need to specify what exactly you mean by "out of pocket". With option 1,2 & 5, the customer still covers the entire cost of the ticket, just not with a single cash transaction. I've certainly done all of the above at some point.
Even when you buy straight business, you can safe a lot of money buying the right fare class: for example on United a P or Z fare is drastically less expensive than a C or D fare, which is again less than a J fare. $10,000 seems harsh. At the moment you can get transatlantic for less than $3k and Australia (furthest destination) for less than $7k