USA is still much smaller than Russia though. Unless you also count the part of Antarctica USA claims sovereignty over but if you do, you also have to do that for Britain and Norway, making them almost as big.
But land area isn't really what matters the most, it's the international power that is important. The British Empire at its peak didn't only control its colonies, it also had susbtantial power over nominally independent nations. Marauding English nobilities could do pretty much whatever they liked anywhere they liked safe in the knowledge that if they got caught, Britian would send a gunboat or two to the rescue.
US power is partly because of its strong military forces of course but mostly because it controls the de facto world valuta. Most international transaction are done in US dollars and 60% of the world's money reserve is still in dollars. Not only does that give the USA a lot of control over the economy worldwide, the dollar itself is an important export article. And it also makes the nation attractive to entrepeneurs and highly educated experts who come there to get their projects financed or find a well paid job. Silicon Valley may be in California but the vast majority of the movers and shakers there are immigrants.
But this has slowly but surely been changing ever since the dollar became a fiat currency. More and more of the international economy is based on other valutas and more and more of the top notch engineers and entrepeneurs find opportunities in or closer to their native nations. It has been very gradual but it can accelrate. Imagine if the US government forgot about the "give us your hungry, your tired, your poor" slogan. Imagine that they also started to "weapoize" the dollar - actively using it to put pressure on other countries and breaking the world's trust in it. Then imagine the FED suddenly decided it was time to push a fresh trillion of dollars onto the market over two weeks. Is this all hypotetical? Well, no responsible authorities would even think fo doing anything like that of course but if it happened, it would certainly significantly weaken USA's international power - not over night but quite fast.
Socialism as it was originally defined by Henri de Saint-Simon (long before Marx hijacked the word and distorted its meaning into something completely different) operated with two different kinds of people, workers and idlers. Not workers as in factory workers but as in anybody contributes to the wealth of the nation, farmers, farmhands, teachers, scientists, merchants, artists, busniess owners, entrepeneurs etc., etc., etc. Of course we are all a little bit of both workers and idlers but some are more of one or the other.
A society is in trouble when there is too many idlers and not enough productive workers and it's in serious trouble when the idlers take too much of the reward away from the actual contributors. The worst case is when the idlers become idolized and generally regarded as "better people" than the honest workers. Why would anybody want to do a honest day of work when there's more moeny and prestige in pushing papers around? This is a sure sign of decadence - a well advanced stage of decadence even - and I think we can see it clearly both in the British and the US societies. (This isn't about socialism btw, it goes far deeper than any political ideology. I only used that as a convenient starting point.)
What really, really worries me is, can we see the same signs in the rest of the western world?