Microsoft's approach was different: let others innovate, then we'll dominate. Others would come up with new stuff, and Microsoft would "embrace and extend" whatever got traction in the market by adding it to their near-monopoly OS/app stack at whatever price served the purpose of eliminating the inventor and taking their market.

This strategy always made Gates paranoid, because the risk was that some alternative to the MS stack would take off too quickly to be killed. Without their near monopoly power as a weapon, they would have no special competitive advantage.

What they feared happened in the mid-90's when the Web took off and the browser/Java combo threatened to be a universal VM on top of every PC. Gates fought back with every weapon he had to fragment the universality of the meta-platform. He was able to greatly slow, but not stop, the emergence of an OS-independent Web, because he controlled the majority of the OS market underneath it.

But then the second shoe dropped. Mobile came along and MS was not able to stop its explosive growth. The growth of mobile made MS just another minority OS underneath the Web, and they lost their ability to disrupt the standardization of the Web platform. They were in the position they had always feared: having to support the standards of others or be abandoned by their customers as the Web became the new monopoly platform.

If Ballmer could have created the mPhone and mPad and given away for free an mOS for phones that was a mini, modified version of .Net, maybe they could have kept the Web fragmented and continued their platform dominance, but whether that was even possible (MS did things second, not first, was only a minor hardware developer, and seldom gave things away except when tied to something they sold), I'll never know. Gates got to wield monopoly power; Ballmer didn't.

MS's monopoly-based business model has to be abandoned, but do they have any other? They'll come up with something, as IBM did, but I don't think they'll ever be leaders again, because they didn't really "lead" before, except in market share.

Google's business model (expand the Web platform for free, dominate Web advertising, and employ an army of PhDs looking for something besides advertising to do) is nothing like Microsoft's. If they ever lost advertising, they'd go down harder than MS, and they could lose it if they ever lost much search mindshare.

And Facebook? They're a website. They are completely dependent on the psychological inertia of their users, which I wouldn't bet on long term.