Even that has nuance. When someone is proposing something that has been tried before, which is common enough, one can point to the relevant historical examples. But sometimes someone is trying to propose a variant on something that hasn’t worked, with the intent on fixing whatever the problem with the idea seemed to be, which depending on if that variant has also been attempted or if there are obvious problems with the proposed fix, may or may not be worthy of further discussion.

It doesn’t help that a lot of labels used to describe political or economic systems are extremely broad, a bit vague or have contested definitions, or are commonly misunderstood, because you can get an idea with some merit dismissed by virtue of sharing a broad label with something unsuccessful, or conversely, someone insisting that this is the case for their idea even though their suggestion really has been tried or clearly doesn’t address the issues with whatever they’re basing it on.

It should be taken into account that some amount of trial and error is probably inherit to developing new systems or laws, and the nature of trial and error is such that anything that works is likely to be preceded by similar things that did not, or at least not as well.