Non-state entities have made all of the USA's rockets.
They weren't reusable because at the time they weren't cost effective. It's only recently that material sciences has reached the point where reusable rockets are potentially cheaper than single-use rockets (and even then, only after 5-6 launches).
Nobody had landed a rocket that way before SpaceX and Blue Origin did it.
There is nothing fancy about Falcon 9 rockets materially wise as far as I know. The key innovation was in the control software and using software industry style rapid iterations to try again and again until they nailed it.
SpaceX developed rockets at much faster pace and lower cost than the competition thanks to this iterative approach vs the water fall method used by the competition which cost 10x as much and is significantly slower.
Your talk of material science would be more relevant to the space shuttle I think. That was an attempt at reuse using sophisticated technology and materials. The spaceX innovation is reusing a cheap rocket. NASA developed a reuse system based on a very expensive and advance design.
Let's not give SpaceX accomplishments that weren't actually theirs - it makes it easier to dismiss everything else they're doing. The DC-X did this (as a sub-scale SSTO demonstrator) in the 90s.