Stefano Domenicali has blamed development money wasted on KERS as the reason for its competitive struggle in 2009.
Other big teams, including McLaren, have also blamed their current struggles on having focused for too long on the 2008 title, rather than on the sweeping new rules for this season.
But Ferrari boss Domenicali said crucial funds amounting to "millions of euros" was thrown out the window on expensive KERS technology that he now believes was a "flop" for the sport.
"A lot of money was spent without the desired effect. Let me put it this way: if it had been spent instead on the car, Ferrari would now be just as fast as this Red Bull," he insisted after the British grand prix.
At Silverstone, Ferrari's Maranello built cars were the only ones featuring the controversial energy re-use technology, after McLaren, BMW and Renault recently abandoned the approach.
Asked if KERS was a failure for F1, Domenicali answered: "That is something easily said, but it is true.
"For passenger cars, KERS is the future, but in formula one we are in a different environment. For us there are too many compromises: ultimately, it is all about the speed of our cars."