There is no arbiter of absolute truth. However, sometimes there are clear cases of falsehood.

This data is from the national broadcaster in Australia which aligns pretty moderate from all studies. The fact that the two major parties show about the same would defeat your hypothesis on its own.

I agree that the data can skew based on choosing what to fact check, but to say this was a long con over 20 years to produce this graph is ludicrous.

Fact checkers are not ideal but the lack of fact checking allows more falsehoods to propagate.