I think it's worth pointing out that really none of Michael's companies, other than MP3.com, have been even remotely "successful." Linspire, MP3tunes, Sipphone, Ajax Windows, are all small startups which haven't had much impact, certainly not to the extent of their competitors (Ubuntu, Red Hat, Skype, Google, and so on).
Even MP3.com was never really very profitable, but Michael was lucky to have sold it at the right time, after he seriously destroyed its valuation with all his copyright infringements with MyMP3.
Until proven otherwise, Robertson remains a one-trick pony.