Profit Capture of Incumbents. See the graph under the link provided (source: Morgan Stanley). In 5 years, Incumbent operating profits from the mobile phone industry went from 100% share to 39% share. If this is not indicative of a successful (i.e. disruptive) entry, I don’t know what is.

I should also point out that Symbian, Android and Windows Mobile hinge their business strategy to the Incumbents (mostly, though HTC is among the entrants and is muddling along).

As a rule, when an industry is being disrupted, making a bet on the sustainability of the incumbents is always a bad idea. Case in point: building a business that sustains the music labels today. Why would anybody pour resources and tie their career to that logic?