I do not "think that Apple is failing as a company." However, they are in fear of losing their halo and the $60 billion dollars signifies inertia based on that fear. Here's the dilemma - purchasing a $20 billion dollar company with another $20 billion in unrealized value probably means the acquisition target is perceived as troubled. Getting involved in that kind of mess doesn't damage companies such as HP, the perception is that they are used to dealing with messy management issues. But it is easy to see Apple's halo easily tarnished by a pursuit of a company like Yahoo! or Foxconn. And even after spending $20 billion Apple would still be under dividend pressure.
As for the Mac App Store, I did not "call it a failure" either. I pointed out that Mac Apps was a lackluster announcement - calling it the highlight of Back to the Mac is faint praise for anyone but the faithful. Apple boosted Mac sales by requiring a Mac for iPhone development, but with the growth of other mobile platforms, Mac sales are bound to slow. The Mac App store is a rearguard action and although a sound business decision because it's so cheap to implement, is clearly uninspired.