If everyone employed some basic "checks and balances" to their decision making, no one would get scammed. To me it's quite logical, sort of like driving a car; "If intersection isn't clear, do not proceed, wait until intersection is clear". Simples.
True, if everyone were completely logical and had perfect information, nobody would get scammed. But people are not completely logical and do not have perfect information.
However, the line of reasoning you just articulated happens to be the exact line of reasoning that makes intelligent people more effective marks. Note that I mean "effective" in a particular way: not that they are more likely to fall for a given scam, but once they have fallen for a scam they are more likely to not believe they got taken.
This is just a variation on another human thing that has been known for a long time: the more intelligent a person is, the easier it is for them to adopt and believe really weird things. It's because smart people are not robots and are influenced by emotions just like everybody, but smart people are better able to come up with a line of reasoning that enables them to come to the conclusion that they have already decided they want to come to.
This is such a potent issue that many of the mechanisms for how science is done are directly intended to try to counteract that problem (through peer reviews, etc.) -- because if you do nothing about it, researchers will tend to "prove" the hypotheses they want to be true rather than the ones that actually are.