It's a different type of fear.

Competition from a completely alien culture can generate mobilization, i.e. different societal strata working together for a common purpose. This is what the US is doing with China today, or did with Japan in the '80s.

What the USSR generated was different: it was the fear that the lower classes could band together, overthrow the established order, and actually succeed in running the country. It wasn't an attack from an alien culture, that the establishment feared; it was successful subversion from within. There is no fear of that when it comes to China.