Seems like people just want semi-instant gratification these days. Games used to be tough to get through, when you said you clocked a game it really meant you knew it because you had to get through all these "time sinks" and problems to get to the end. The upshot was that when you got to the end and beat it, you really beat it.
"Time-sinks" may not be wanted in this new wipe-my-ass world, but being punished and set back in a game is a large part of accomplishment it takes to clock the game. It's all analogous though to the people that go to the arcade with a pile of money and just continue until the game is done... they spend more money and wont have the same satisfaction of clocking it without continuing. It's a good metaphor because these "no time sink" people will spend more on games as they finish them faster.
But it's all fine as long as there are products for everyone, and that anyone looking for old-school challenges can find games like Ikaruga