Investors have learned to research projects and learn how to choose promising ones. So I think that Scam soon does not remain. Investors become are smarter.
I won't say this if I were you because we can't all have the same knowledge and I have seen members of this forum which got scammed not to talk crypto investors which enter the market because of the benefit involved.
I do not think that scammers have a strong negative impact on investors.
Scamming issues does have negative impact on the market and investors because crypto scamming was one of the reason why some government in the South America banned Bitcoin during the last ATH