Because the previous ones blew up. As simple as that. They naively think the new ones will be better, until they blow up again. Thus, a neverending cycle.
Yes, new blood would explain the hiring spree. But, they are not all traders contrary to what was said. they are trade checkers, trade support, margin clerks, & back office people on a whole. They are the support staff that handle the volume of the trades. It may be just a good time to position yourself after the credit implosion if your a bank, FCM, or brokerage. One thing is certain though they do not hire up in the futures business if the volume isnt there. & if prices rise, mkts invert you will see volume. Tail vs dog...doing the wagging.
A year & half later...... I think their planning prep is probably paying a dividend. Crude has been moving.