I'm not involved enough to know the facts about what Cobra charges, but from what I've heard from various parties "at the beach", Cobra have rather used their position to _dump_ prices, keeping other factorys out of the equation. Remember, building a board is still involve a lot of human labour and you can pretty much reverse the argument above and ask yourself how much the workers at Cobra makes and if that is decent or not.
From what I heard, a large part of the increased prices has to do with the workers at Cobra getting payed better which, in the big scheme of things, is a good thing (remember the strike a few years back?). Maybe Cobra as a factory takes out a bigger profit as well, but that's just not what I heard.
And since there in fact ARE other factories (Tunisia, Taiwan, China, SLovenia if I remember correctly) the monopoly argument does not hold. AHD, Mistral, T1 and Witchcraft are some brands manufacturing outside of Cobra. Moreover, if we look back 15 years, boards were more expensive than now (if you include the inflation.