How? He’s saying that he can’t think of any good ones, and in my experience that’s true of most informed people. This is one of those hard problems that needs solutions, and so far the present system is the best anyone has managed.

I don't care what he's "saying that" which is just your biased interpretation. His essay does not warrant the final concluding sentence which would require a different essay thesis. It's just basic high school reading and writing skills.