You're right, it's not that simple. You must observe the qualifications of the population you survey to determine who believes what, and what qualifies them to know the facts.
The fact is that virtually 100% of the professional scientists that study ancient species accept that Evolution is a fact. They discuss and dispute various details of Evolution theory, but they have no doubt as to the fact that Evolution occured.
This is simply a rephrasing of the same fallacy. In 1880, 99% of physicists believe light was propagated through a substance called Ether because they knew that a wave required a medium of propagation. These were all highly intelligent, highly knowledgeable men in their fields with impeccable credentials.
According to your criteria, nothing should ever have been done to question that assumption because all the great scientists of the day accepted it as fact.
Fortunately, unlike evolutionary biology, physics is an experimental science, and men actually went and looked for evidence of ether. When they couldn't find it, they turned to another mechanism to explain the observed propagation of light as a wave.