If parsing is needed to clear challenging content then why is it not in the game?

[Kitfox]

You already have that. If you fail a DPS check something happens and everyone knows it. It's not some mystery that waits until you're at 1% on a boss before randomly killing everyone. Enrage timers aren't some profound and mystifying concept, either. A parser is useful for seeing weaknesses in your group and in yourself, but it's far from actually necessary to accomplish things.

Parsing just gives you more information, and it doesn't need to be built into the client for you to take advantage of that information.

Well, I mean, simply dying is about as useful as only giving you a number and no information behind the said number. For the same reason I'm not really vouching for an in-game DPS meter, because I have serious doubts it'd be as useful as ACT+FFlogs are.

I'm pretty happy with the current situation, although I feel bad for the console players that can only get their information indirectly.