I think people are more willing to accept musical drama than musical comedy as being timeless. I think Silk Stockings has a very good musical comedy book with some terrific gags. I think it has a better book than score. The ballads especially lack the Porter finesse. Chess is harder to figure out because it gets rewritten with just about every major revival. I didn't care much for the London album of Chess but I really liked it on Broadway. But I think the Broadway production failed because it was so different from the London production and alienated the already established fan base.