This is quite amazing how much they spend on adwords, according to a leaked report: http://www.techworldpost.com/33961leaked-report-apple-intel-spends-1m-per-month-on-adwords.html
If they have money, why not to spend? The problem is for small guys (which is majority), there is no much room left for them. All popular terms become very expensive and you always see the same advertisers in a first 10 places.
Adwords is expensive... I'm not at all surprised. Even for very small businesses, up to $1000/month is not unheard of, so I'd be rather surprised if Intel and Apple weren't spending 1m/month...
One of my clients use to spend 6-7K/mo on PPC with Google and close to that with Yahoo and he is not even a huge company at all.
AdWords is Google's core revenue stream. Because they have the best search results, they get the most searchers. Because they get the most searchers, they get the most advertisers. Because they get the most advertisers, they get the highest price for keywords. What is even more amazing to me is that no other company has been able to take market share from Google. Bing is Microsoft's first *decent* search engine and after all these years and I assume billions of dollars, they still don't even come close to being a threat.
Adwords is so expensive, and is not suitable for small companies. Big companies has a lot of money, and they become big clients of Google Adwords.