Those American forces also had vastly longer supply lines to sustain. What the Russians lack in financing and capability, the make up a lot with proximate borders, time zones, etc.
There are plenty of sayings along the lines of "America doesn't have military, they have a logistics corporation" Supplying enough "X" is rarely an issue for the USM except in the cases where it is something new they didn't realize they needed.
The US has established bases all over the globe and has basically created a worldwide supply chain for its military, so that isn’t really a factor. (Please note, this isn’t being said in an anti-American way.)
Russian military morale is so low it's almost a non-force. You see them unloading into chicken farms and monuments rather than fighting. They are running out of fuel all over the place - probably because they sold it. The corruption in the Russian military is vast and intense.
It’s interesting because the U.S. has an order of magnitude more military funding and was trying to secure a supply line an order of magnitude longer. I wonder if this ratio makes it approximately as difficult?
American supply lines were vastly superior to what Russia’s doing with its clown convoy however