The reason most (business) people buy C class tickets is for flexibility (i.e changeable/refundable tickets) and a small amount of extra comfort, usually in the form of a free middle seat, perhaps the odd extra inch or two pitch in the first 4-5 rows.
Some of us who travel frequently also have corporate deals, so these tickets, whilst substantially more than a discounted M/S/T etc class fare are usually rather less expensive than a Y(early) ticket, as previously pointed out by TRSS.
Also, we get more luggage allowance and usually fast track security clearance which really makes a difference at some airports (e.g. ZRH, but not at London), meaning that you can often get another 30-45 mins with your client, which is often more important that it may sound.
As to service on board, yep a few more free drinks (if you need them) and a better meal, but that's not really the differentiator.
I'll pay for the service on business, but on hols I'll take economy every time.