Well if you are not hiding from the government and just want privacy, then we could just use a centralized mixer.

So perhaps what I mean is that first crypto-currency has to become popular and then we have to work out which forms of privacy are plausible, scalable, realistic, and which the government will allow us to have.

It is not clear to me yet that sophiscated on chain anonymity is going to have a big market. And if it does, perhaps Zcash's algorithm will be favored because afaics can protect better against IP address correlation.

Yet I think next year, Monero will be in the strongest position with mature technology for privacy and a liquid coin with centralized distribution. I doubt Zcash will be that mature by then.