To begin with, the premise would have to be challenged. Many, many bad regulations are bad because of incompetence or corruption rather than because better regulations are impossible. But let's consider the case where there really are no good regulations.
This often happens in situations where e.g. bad actors have more resources, or are willing to spend more resources, to subvert a system than ordinary people. For example, suppose the proposal is to ban major companies from implementing end-to-end encryption so the police can spy on terrorists. Well, that's not going to work very well because the terrorists will just use a different system that provides E2EE anyway and what you're really doing is compromising the security of all the law-abiding people who are now more vulnerable to criminals and foreign espionage etc.
The answer in these cases, where there are only bad policy proposals, is to do nothing. Accept that you don't have a good solution and a bad solution makes things worse rather than better so the absence of any rule, imperfect as the outcome may be, is the best we know how to do.
The classical example of this is the First Amendment. People say bad stuff, we don't like it, they suck and should shut up. But there is nobody you can actually trust to be the decider of who gets to say what, so the answer is nobody decides for everybody and imposing government punishment for speech is forbidden.