It seems the camera took a lot of blames for missing the focus, so the logical next step is to find a better camera that won't fail. I think differently... I think they are relying too much on the camera to take the photo, and since we don't yet have artificial intelligence running in our cameras, they are bound to fail sometimes. They don't know exactly who you want in focus, what part of their body you want in focus and not in focus, and they're not tracking the subject you want to anticipate their movements. This is exactly what I learned after shooting with a manual focus camera like the M9 after a few months. You learn to relax the depth of field, you learn to move the camera with the moving subject, and you learn to anticipate their movement forward and backward with your focus so you can nail the shot even as they run toward you.
Of course, I don't nail the shot 100% of the time. However, when I fail to nail the focus, I knew it was my fault. No need to get another camera, I just need to practice more, or try a few extra exposures to be sure. Now looking back, I've been shooting the M9 for almost 3 years and the camera itself is over 5 years old, and to me, it's just as awesome of a camera as it was when I got it.
I heard a great quote by Craig Semetko in a Leica ad:
"For me, the Leica M is the path of least resistance between what I see on the street and a final print in my hand."