Exactly. Hegel developed a theory that historical progress goes always forward, or towards better things. Capitalist-based theory says that Capitalism is the inevitable outgrowth from Feudalism, which is false (Meiksins-wood showed that Capitalism is an idea that was enacted through force, not an inevitable outgrowth of the previous systems). Communist theory says that Capitalism inevitably fails and tends towards Socialism, which eventually develops into Communism, which has yet to be shown. People tend to think that Evolution results in better and better organisms, rather than those that convey the best advantages for it's environment. For some reason lot of people tend to think that a society's values will get better over time, and that modern societies are qualitatively better than those from thousands of years ago, rather than just different.
Hell, even here a lot of people believe that technological progress is a linear path towards the future, even when there's evidence contrary to that assumption. Without even reaching for evidence from other fields, it's trivial to find examples of entire theories that have been forgotten and rediscovered. Think of Low-Density Parity-check codes, that were developed in the 1960s and essentially forgotten for 20 or so years. A lot of technology has been found and then lost.