Isn't Fiat more attractive than Bitcoin for criminal activities? You can see there are other intentions besides preventing criminals from using a crypto mixer. With heavy pressure from the government, it's likely centralized mixing services will cease to exist in the future. At least, we won't be left "empty handed". Non-custodial (decentralized) mixers will ensure people get the privacy they deserve without fear of censorship or prosecution. As long as developers stay anonymous, no government will be able to stop people from using these services . I wouldn't be surprised if governments decide to hunt privacy coins next. Who knows if someday it becomes "illegal" to use a privacy-oriented cryptocurrency? 
currency regulations about money service businesses are not new. but governments were slow at understanding bitcoin to know whats a money service business.. and.. people wanting to run money service businesses are slow to realise their service is one
but here is where people need to learn.. by reading regulations. what makes them defined as a MSB and then tailor/customise their service to not be a MSB
if you are literally advertising a service that says its function is to take money in, and for a fee process it and hand it back out.. its obviously not advertising itself as a retailer/merchant. nor a taxi cab loyalty point system.. but advertising its a MSB
so these businesses that want to operate without MSB regulations need to think smarter.
bitcoin has been known to be a currency and fill the currency jurisdiction for 10 years. so while still defined as currency in law makers definitions means businesses have to see if their business fits the currency service business.. or is instead a retailer/merchant/auction/property manager