Cash exists, the same can apply to cash.

The answer, the insight is, everybody wants private money. They just don't want *you* to have it. They don't ban cash, not because they can't, but because they want the option for themselves, they being the crooks in government. So, they'll always let something continue because they benefit from it.

A completely private decentralized network is a far cry from a mixing service, one is just a thing people use for whatever, the other stands out like a sore thumb. They're much less likely to go after the former than the latter, again, primarily because they need it as much as you do.