Those admittedly superlative optics are also tied to a noisy, slow, autofocus system, with a not so great viewfinder. (not really the case with the 21mm which uses a separate finder).
I own some sharp lenses for my Leica, but my favorite remains the 50mm f1.4 Summilux which doesn't get very good reviews, but has an image quality which lends itself to people pictures.
It's not about the camera or lens, individually, but the package. The Leica has never been equalled. Consider this a spitball across your bow...