We have so many traders who have come from the "salaried" firms and are so upset at giving away so much of their profits. When you trade a couple of months, and make some money, that money is yours (effectively), and you have now "put it up with the firm" without benefit of full payout.
No firm is going to pay you to lose money for them, and if you're not generating enough commissions they will let you go. Even the "big boys" have cut way, way back on their "no cash upfront" programs. The model just really doesn't seem to work since the "bubble burst."
Even the Street firms (GS, ML, etc.) have heavily cut back their trading desks. The good traders go out on their own, put up a limited amount, and keep their profits. The rest are soon looking for another job or are "locked in" with tricky "golden handcuffs"...IMO.