The solution you give is both simple and extremely effective; why don't people do the same as you and go looking for more trouble? We don't have to do anything, we don't have to determine who should enter the market and who shouldn't enter the market. The only thing we need to do is stay away from those toxic things, everything will be fine.
Currently, there is no other option for traders, but as long as they withdraw all their funds at the end of the business day, they are safe, don't trust exchanges and use them only when needed.