Yes, they can fill their spots, but the reality is that hiring bullshit means that over time their candidate pool progressively filters to "the people who will put up with bullshit", and while it takes years to filter through, in the end you up becoming Microsoft.
There was a time when Microsoft was the bee's knees and was the elusive dream employer. Then they started various HR initiatives and it became a place that only a certain type of person wanted to work, and the result is the malaise and technology lack of leadership that Microsoft now evidences.
HR as a profession is often a scourge, and the more influence HR has at a company, the more inertia pushes towards decline.
Get your HR droids on a leash, folks, before they kill your company.
They were doing just fine making things like Google Reader.
I suppose now Google is more balanced and their stock is much more valuable but their long term direction has changed significantly. They can now be disrupted.
Isn't that the case already???
Most people joining big web giants I know are generally the kind of people who don't do any great real work but practice hours daily and spend insane amount of time on interview sites, take huge efforts in achieving expertise in one thing and one thing alone 'clearing interviews'.