Not necessarily a bad thing, either
I get the sense that a long-term "leveling of the playing field" is probably inevitable, and isn't necessarily a bad thing, even for the US. Other nations will expect less from us, we'll be hated less, we'll probably (hopefully) leave a much smaller footprint on the ROW, and maybe we'll find ourselves more interested in addressing our own shortcomings and less concerned with how other people lead their lives.
Having less influence in the world doesn't mean we'll shrivel up and blow away.