Ask United Launch Alliance, they are the ones who bought the engines, our government paid them for their rockets. (That were made with the Russian engines.) I seem to remember reading that there was a 2 year stockpile of them yet to be used.
But I've one question: If Dragon survived the explosion, why didn't it deploy its parachutes? I mean, this wouldn't hurt anyone, because Dragon has landing capability anyway, but it would at least increase the chance to retrieve maybe some of the expensive payload...
SpaceX designs, manufactures and launches the world’s most advanced rockets and spacecraft. The company was founded in 2002 by Elon Musk to revolutionize space transportation, with the ultimate goal of making life multiplanetary. In 2010, SpaceX became the first commercial company in history to send a spacecraft into orbit and return it safely to Earth. In May 2012, SpaceX again made history when its Dragon spacecraft became the first commercial vehicle to successfully attach to the International Space Station, something previously accomplished only by governments. In October 2012 and March 2013, Dragon again successfully delivered cargo to and from the space station in its first two official cargo resupply missions for NASA.
For more information, visit www.spacex.com.