Success? Hmmmmmmmmm. Better kill that project.
They didn’t cancel it because it was successful. They cancelled it because it was only marginally successful, with big cost overruns, and other technologies proved cheaper and more effective. We don’t have to rely on the speed of lasers to intercept projectiles anymore, because we have better targeting and guidance systems, so we can hit a missile with a much cheaper and more reliable weapon than a laser.