The problem is that the people who need to be convinced are not the people who are being harmed by phishing. The people who are being harmed by phishing (non-technically-savvy end-users) are powerless. The people who need to be convinced of the merits of the solution are browser vendors and web site operators. Both groups would need to work together to solve the problem. Getting that to happen is the hard part. It's a very real problem, but it's a political problem, not a technical one.