In the first 150 years of constitutional government, 25% of America's presidents had served as heads of Cabinet departments. Since then, we've had no President and only one Vice President (Cheney) come from the Cabinet. With a notable exception still undetermined, when did Secretary become a last stop?
I don't have a good answer to your question, unfortunately, but I feel I should point out that Herbert Hoover served as Secretary of Commerce, and Taft was Teddy Roosevelt's Secretary of War.