The problem is that most of these developers are the ones making these outlandish claims and rather than be honest from the get-go, they sell you all kinds of false promises and when the final product is released, they expect us the consumers to buy their product without holding them to the promises they made. There's a thing called competition and if companies aren't as good as their competitors, they'll be left behind in the dust - that is true of any business sector. A lot of it also have to do with how game has been marketed, if the marketing strategy is executed well enough, even a mediocre game can be a hit at least in the short term.