It has... But the thing is that ZCash founders are taking a cut from mining profits and there is a hard fork of ZCash called ZClassic that is currently operating which doesn't take the cut. ZCash founders essenitally get 2.1 mil ZCash for doing nothing.

Plus, ZCash's privacy is optional. It can operate just like bitcoin, and every transaction can be seen.

I think bitcoin is adequate if ZCash only has optional privacy anyways, as long as you use a bitcoin mixer and don't reuse bitcoin addresses there is very little chance you'll get traced.