Directly, bitcoin can't be regulated, yeah, I agree with you cause in case of fiat the government can even change the currency, print more or even withdraw from the circulation but in case of Bitcoin that's impossible to do. But... When the exchanges and bitcoin related services are regulated, this at some point means that bitcoin is regulated too but the influence and power is lower there compared to fiat. As time goes, more and more bitcoin exchanges are regulated and more often you have to submit KYC documents (including exchanges, crypto casinos and so on). Also, mining has turned into centralized business, there are just some giants that mine most of the coins + more and more transactions are easily traced as time goes. This only just means that bitcoin is getting more and more "regulated".