Capitalism more efficiently allocates the labor of people than a command/communist economy. Thus, for the same population, a capitalist economy has more wealth -- it can spend this on better consumer goods AND better military hardware. The tokens themselves don't matter.
As well, the "western world" was much bigger and better resourced than the soviet bloc, and started from a much higher level of development.
It's amazing that the soviets were able to maintain some level of parity as long as they did (maybe to 1960-1965 in most military forces); for some things, playing catch-up was easier than initial development (nuclear tech, lots of other weapons, many consumer products), so it was easier to remain in a close second place than to potentially be the leader.