I don't think this is the case - disclaimer, I worked at King - if you look at the top 5% of Zynga/King users with respect to revenue, you won't find hardcore gamers, but rather your usual casual gamer but with lots of money to spend. The 'hardcore' gamers won't pay to lessen the challenge. The problem with your idea of creating hardcore games is that it doesn't appeal to most mobile phone users, hence limiting the $$$ making opportunity. King IS now branching off from super casual, but only in a limited way.