There is one thing I think you get slightly wrong.
Sram and Shimano are blatently bigger than Campagnolo - as you quite rightly suggest, however Campagnolo is concentrated soley around Performance Road products, where as Shimano and Sram are larger in other areas. I would suggest that in the Premium Road Componentry, Campagnolo is still the largest. It is also their only source of income - hence why they market their produce so heavily in the pro tour scene. Sram and Shimano have other areas to devote attention too!
There is also Pedigree - Shimano's success in Road cycling is reletively new - they first won the TDF with Lance - which is not that long ago.
However, I do think that Campagnolo pay a large amount of money to keep themselves as first choice of so many Pro teams worldwide. The best example of this is Quickstep - They ride a bike that until this year was not sold by Specialized as a company. In fact, I would suggest that it would be a bigger benefit to Specialized to have Quickstep riding Sram or Shimano, like Saxo Bank. However, Campagnolo have held onto their position, regardless of what Specialized were probably calling for. I'd assume for Campagnolo it is vital to their strategy to keep themselves at the top and they will continue to do so.
Elchingen - I can't imagine a world where I would have to repair my shifter? Even if I had a Campag Shifter and it broke, I would still be replacing it. In the past years of rather heavy Road riding, I have broken 2 Frames and plenty of Rear Mechs etc, wheels, chains etcetc. I have never, or even come close, to need a repair on a Shifter. Infact, the only spare part I have ever needed is the little Ultegra signs on the top of the shifter, that got scratched in a crash, which Shimano do sell.