> If modern finance prevents scams better,

Its better at preventing a type of scam, but significantly worse at legal scam -> how much is an 8% inflation of the dollar on dozens of trillions of USD denominated financial instruments?

And there is also plenty of equity scams that are sanctioned by government - the kind that suppresses the ability of people to invest or get funded, to give special permissions to those that play the rules, etc. The way some get bailouts at the expense of the rest.

A system with a high degree of freedom and lack of oversight will have higher scams. The big question is, if people were given the choice to participate in both systems, which one will thrive?