1) Most of these companies have been there for many for decades, Google is relatively very new (infact I think Googles age is less than 1/2 of any otehr in the list) 2) Googles domain is very specific/restricted as compared to what you have listed. Getting a patent is not very easy in algorithms/software (may not be hard either). Infact, globally, in the area of data-mining (web search etc), I think we wouldn't have patents more than rate of 20/30 per year. I may be wrong but that my guess according to my knowledge of the field.
