Actually, that's not true at all.
Jerry Jones was one of the largest proponents of the salary cap. The reason why the owners wanted it instituted was to limit the cost to owners once free agency came to be. As much as these guys want to "win", they are businessmen first. And, prior to the cap being instituted, the Cowboys salaries were relatively low due to the age of the roster.
Keep in mind that in 1993, Jones said to Emmitt Smith during their contract negotiations that he (Jones) would walk across a desert for a dollar.
The salary cap is not a bad thing at all. It rewards those that scout well, plan well, draft well and run their organization properly.