Inventors in the USSR were paid just as well, if not better than, their American counterparts. Mind you, this is not a defense of the USSR or authoritarian communism, Stalinism killed many people. However, maybe educate yourself on how these systems worked before critiquing them. A critique of communism does not negate critiques of capitalism.

Also - be careful with conflating inventors and capitalists. Inventors are often laborers who have their work profiteered by from the owning class - famously, Nikola Tesla lost control of his patent for AC motors and was left penniless as capitalists formed a new utility company.