All this stuff was intended for the defense of the United States. Russia has not been on our radar screen as a serious conventional military treat for 30 years.
There isnt a need for even 10% of the US military if it were only about defending the territory of the US.
Russia HAS been on the radar as a conventional threat. More potential than actual through the 1990s (how to deal with a messy civil war scenario say), much more so through the 2000s.
Thats why the US maintains 20 Army+National Guard divisions equipped for continental scale combat, plus reserve equipment for almost triple this force.