No matter what is better, Monero or Zerocash, just don't think they will be something very big like 'the next Bitcoin'.
The actual demands for privacy and anonymity is actually small. For many people, Bitcoin's privacy is enough.
I talked to the son of a billionaire about using Bitcoin personally and for the business he is in (Oil).
He is smart and young and did his own research and in the end had to advise his fathers company against it and also decided it's not good for personal use. I asked him to explain. He said that he can't see any real business accepting the system because it's far too transparent.
Imagine we are in a Bitcoin centric world. You can easily get bitcoin into a company or to a friend (buying or gifting) and then you can watch their wallets. Bitcoin gives real time information into things like what investments you're buying, when and where you bought your local coffee and so much more.
The transparency provided by Bitcoin is creepy and invasive. I remember explaining this reality to my Dad when I was getting him into Bitcoin just a few weeks ago, he was amazed it had grown this much with such a massive hole.
Bitcoin is less private than using paypal, VISA, MasterCard or your bank. Because in those situations a trusted third party knows your business but the world at large doesn't.
My friend said his company can never use it, the competitive advantage it would give to other companies would be too much, they would be able to tell how much cash flow they had, where they send their money, what contractors they were using.
I personally have always been a little bit into the "we must have privacy! Bitcoin isn't enough!" line, but since talking with real world people it became obvious how bad it really is.
I doubt you are right.
How many bitcoin millionaires think twice before sending $10 for a pizza from their wallet, so much of this can be traced and it'll get worse in the future. Companies are popping up to put as many company and individual names to addresses as possible.
This technology is needed.