You all know none of the relevant countries today are governed by either system right? And nobody in those countries has discourse anywhere similar to how you do. If at all.
The US always was a mixed-market economy based on classical liberalism principles, not democratic, not conservative and not necessarily capitalist. This was the case for Teddy Roosevelt, the closest to a socialist president, although mildly. More democratic socialist.
Russia is an authoritarian capitalist country with elements of a police state (de-facto, not derogatory). So are Poland, Hungary and Turkey. All these countries technically achieve things and are more of an example of working systems than the one you consider, putting away the moral side of their policies (concerning destabilizing the EU, proxy wars, highly statist, centralised power).
They don't need to invest trillions on foreign policy to do that.
China is weird. A mixed, wholly centrally planned, targeted distribution economy, governed by a dengist model. That is democratic socialism, conservative socialism socialism and state capitalism, under Xi Winnie the Pooh sometimes culturally variable. A syncretic system.
Much of what is apparent in the US as problems isn't in those places and as much as their citizens are unaware of how much danger will set upon their country, because they are often largely stuck in the past, comfortably, they have a much more nationalist, central and aggressive view of their country and attribute everything to it.
Proportionally they have high percentages of available for military conscription young people who are ready to die for their country in combat. This percentage in China is 71 if I remember correctly. Even if a much larger sample is polled and the percentage drops in half, that's still 35% and imagine how much people it is.
Also, the axis are definitely in favour of Russia and China. Much more countries would support Russia than America in a war. Military expenditure and exports may be smaller, but the countries supplied to is also, much more.
And of course, over the course of Vietnam, Iraq and Afghanistan, we learned America was largely inefficient as a large force. Tactical units and federal agencies have had limited success, for little gain. Nothing to gain by capturing and killing Ben Laden after 9/11. Terrorist cells are popping up all over the place, like the vietcong out of rice fields. And all Americans can do is sadly, record a shooting at a mosque live on Facebook.
In other words, they have you by the balls and are pulling harder than you pull theirs. (Unfortunately?) America loses.