The US is absolutely an Empire, it practices imperialism, by which it extracts vast wealth from the global south. The USSR didn't do that.
Further, I'm absolutely focused on economics. The Soviet economy slowed, but was still growing. The dissolution of the USSR was multifaceted, complex, and not boiled down to one failure. Further, its conditions are entirely different from the US, which is a decaying Empire, the fruits of imperialism are diminishing and disparity is rising.
I'm a Marxist-Leninist, economics are core to my analysis.