Look at any movie by Sergeï Parajanov, like Shadows of Forgotten Ancestors, by Andrei Tarkovsky, like Andrei Rublev, Solaris, Stalker, or anything by Sergei M. Einsenstein, and find out cinema was quite "free" in the Soviet Union... Parajanov and Tarkovsky had some difficulties, Parajanov even ended up in jail ; but their movies wouldn't have been made by the US industry, at all... (Eisenstein was Stalin's favorite filmmaker, so he had little difficulties in making his great movies. His October still has some of the best editing ever)

Soviet movie makers and cinema theorists indeed built the base of movie theory...

Un roi sans divertissement est un homme plein de misères