It will apply to anyone who interacts with an American based exchange or other service, for now. But we are already seeing other countries start to adopt similar rules, where fully KYCed exchanges will only permit sending and receiving bitcoin from other fully KYCed exchanges. It is quite clear the majority of governments in the world want bitcoin to be entirely contained within a system they have complete power over, and can monitor and control as they desire.
Other countries usually copy America's model, so they will end up "banning" centralized mixers for good. What we will see in the future is a new wave of mixers that are fully KYC/AML compliant. It will look good in the eyes of the government, but it will defeat the whole purpose of "anonymizing" your BTC transactions. At least, we'll have non-custodial mixers to keep us by. I know they will be "illegal" for mainstream use, but people will resort to this option if they want to obtain true financial freedom and privacy. Everything will be done under the radar of the government.
With institutional investors getting in the game, it should only be a matter of time before regulations become stricter. All with the excuse of preventing money laundering and tax evasion. I've thought criminals used Fiat currencies for said purpose? You can see the govermment has other intentions besides "legalizing the industry". It's all about power/control. As long as BTC stays decentralized, there should be nothing to worry about.
