EDIT: To be specific, why gaming companies would let the majority (casuals) determine how they make their games.
The casuals will always be the majority. Lets assume that the average, current casual gamer becomes good and skilled players, almost as good as gamers who participates in MLG battles. Eventually those 'casuals' who improved will still stay at their place as casuals because there still always be certain group that will be better than them.
Millionaires are considered rich and wealthy people but if tomorrow everyone becomes a millionaire, does the status of a millionaire still hold as much prestige?
Gaming companies need to make money. It's not like they will create specificly create more challenging games to target hardcore gamers and create huge profit, like a car company would market models and designs to rich folks. Unless the better quality cost 2x the amount (or more) of the standard edition but how many hardcore gamers would accept that value?
Unforunately we just have to put up with it.
[Edited on 12.22.2012 4:55 PM PST]