It's no doubt SE did it on purpose. They don't want you to play too hard, get the gears as soon as possible and then have nothing to do with the new duties.
If the weekly cap is removed, the possible result is not as simple as how soon you gain the tomes. It would cause some non-hardcore players blamed by their team mates for "not having newest gears to make the raid easier".
In other words, people would indulge themselves much more than we thought, if there was no cap. And SE will not profit from increasing your daily play time, to the opposite, if you get bored too soon, that'll be their loss.