Even with an algorithm, you're still relying on human memory. As Schneier and other have been recommending for a long time, write down your passwords. People already understand some amount of physical security, which is knowledge that can can utilized for password storage.

As long as human memory is the weakest link, password strength will always be de facto limited to the amount of entropy that a human can reasonably memorize. Unfortunately, brute-force password cracking capabilities flew past that limit a long time ago.