I don't think this is factually true. Besides Netscape, he's noted for cofounding Ning and Loudcloud. Loudcloud pivoted almost entirely, sold their old business, and rebranded the new idea as Opsware which had a successful exit (but even so wouldn't be "the best"). Ning I'd grant being successful in the sense of not having died, but I don't think there's any argument that it's anywhere near "the best". It feels like a huge stretch to count that as three-for-three.