There is no if. They will be regulated in the future, would get a bit different name, but the idea under it still will be DeFi. As soon as people will understand how sweet this DeFi pie is, they will try to take a piece of it. This always happens. At first no one cares (or cares, but have a strategic plan), but when it starts to generate huge money, it gets torn apart with rules, laws and etc.
In any case, decentralized finance will first win its fate of the cryptocurrency market, attract sufficient investors and followers to their projects, thanks to which they will receive strong enough support, and later, in order to function legally and have legal protection and legalization, each user and investor will still be forced to provide your passport details. I believe that no government will allow such projects to exist without control as long as the current state structure exists. I believe that for a decentralized financial system there should be political Will, if not in every state, then at least in a separate country.