There doesn't need to be a solution that works for everyone. It doesn't matter how many barriers you put in place, people will always get scammed - so don't punish the other capable 85%.
You mean the capable 15%, not 85% as again users are dumb. That's why governments will always cater to the majority.
You do in fact need a system that works for the vast majority. If your system flat out doesnt work for 15% of the population, you'd have mass riots and unrest.