No, there are tons of different concerns, aspects to protect, and also ways to achieve the things we want. There isn't a monolithic solution, and a zcash drivechain is actually a narrowly useful tool that comes with its own trade offs.

Sure, something like a zcash drivechain would likely aid (depending on where those trade offs concentrate), specifically in the case for privacy, but it obviously wouldn't be a total or perfect solution and is dependent on many other elements.