There's a definite sense of late that all's not well inside a number of big technology companies.

Microsoft has been muddled about its direction for ten years, the nastier side effects of which have been mostly mitigated, or at least deferred, by the fact its Windows / Office cash cow is so large.
Nokia used to be the worlds largest mobile phone manufacturer, now it's betting its future on the Windows Phone OS hoping that Microsoft can save it from oblivion.
Six years ago RIM was redefining what we expected from smartphones with BlackBerry. Now it's redefining the meaning of the word implosion.
HP had the corporate equivalent of a nervous breakdown last summer and has just decided (again) to start manufacturing Tablet PCs. This time running Windows 8 RT. If HP had a face, you'd slap it.
Sony looks increasingly fragile.
Dell is in need of a second act; the mail order PC business isn't exactly ground breaking.
And today Yahoo staggered through yet another leadership crisis and is about to get it's fourth CEO in four years.

And only Apple and Google seem capable of recognising that no matter how earth shatteringly awesome your one great product idea was, it most likely isn't enough. You need to be BATSHIT CRAZY PARANOID - as Steve Jobs evidently was - that your treasured Golden Goose is either going to die or get stolen from under your feet.

Yahoo is a great example of a business that got big quickly with one simple idea back in 1994, but which has been spraying the cash proceeds from that same idea against the wall ever since Google showed and spooked them almost fifteen years ago. They're demonstrating brilliantly that you can't build a sustainable long term business if you fail to engineer the right conditions to make lightning strike twice. And, actually, maybe you can't make it strike twice.

And so I think what we're seeing now is a kind of Newtonian reckoning where the inescapable laws of physics ultimately draw back down to earth anything that lacks the propulsion required to stay aloft.

This stuff really is business school 101. You'd have thunk.