Tripling the salary cap would be ineffective. The salary cap has annually increased almost every year single its creation with the current collective bargaining agreement format. Player salaries have kept pace with the increases.
Subsequently, tripling the cap will triple salaries. An alternative hedge, to the owners (and NFLPA) self-imposed nonsense, would be instituting compensation exceptions like the NBA's Larry Bird stipulation.
It is highly unlikely to happen though. The perpetually reinforced parity system agrees with both the owners and union's wishes.