Sure but then it's like... for example, if you land rockets and your advertisement says "People told me it couldn't be done!", then fair enough. But if you, say, build an electric car and your advertisement says "People told me it couldn't be done!", then ... who exactly have you been talking to?

The phrase "They said it couldn't be done!" is an evocative proxy for technological novelty. If the experts are not representative, the claim of novelty will be misleading.