Why India software/IT industry is service based and not product based?

I have been fascinated with computers, softwares for past many years that during that time only I decided this industry as my future. I have worked both in India and US and has been comparing the differences for a while.
The major one is that US software giants are product based while Indian software giants are service based. Just to elaborate who are not familiar to these terms. Product based refer to the companies who are building something to sell in market while service based companies are providing work for the product based companies. Major product based companies are Microsoft, Google, Yahoo, Hughes etc while service based companies are Accenture, Aditi, TCS, Infosys, Wipro.
If you work for product based companies then you are working on something for years, researching on it all the time, enhancing & improving it ultimately giving you enough time to master the technology which you have been following for years. A drawback is that you are only for that technology. If that one goes off the market, expert will be in trouble. This was the scenario which put many web programmers future at stake due to crash in the software industry mainly in the web technologies.
In service based companies, you are fullfilling the requirement of some other companies so you are mastering as per your client need. You are working on something which you are told to and therefore in a short span of time, you are aware of many technologies but as one is never involved in projects for long time therefore expert is no word here. Even if someone calls you so then also mind doesn't except cause you know you are not. Someone better is nearby who has been working for so many years on the same stuff.

Let's check out the other technical aspects of the two industries

Microsoft

Revenue US $51.12 billion (2007)
Operating income US $18.52 billion (2007)
Net income US $14.06 billion (2007)
Employees 76,539 (2007)

Google

Revenue 10.604 Billion USD (2006)
Net income 3.077 Billion USD (2006)
Employees 13,748 (June 30, 2007)

Accenture

Revenue $18.228 billion (2007)
Net income $973.3 Million (2007)
Employees about 158,000 (2007)

Infosys
Revenue $3.1 billion USD
Employees 75,971 (As on June 30, 2007)

TCS

Revenue US $ 4.3 Billion (FY 06-07)
Employees ~95,000 (June 30, 2007)

Now, if you compare the revenue per employee or profit per employee then product companies are in much better position but still their growth is dependent on external factors and in case, their competitor is able to make space in their domain then they are in deep trouble while service companies are serving to many clients at the same time make them less susceptible to market up and downs.

Still, my belief is that product based companies will be more helpful in growth of country. Because we don't have product based companies, we don't have good search engines, good sites, shopping sites, software, applications which can work in local languages making up proud of using our language on computers like chinese, japanese people have. Only 10% of total population can understand english. So there's a hidden treasure which is still unleashed. If the remaining 90% (Ok, take only 40% as many are not educated) is targeted then one can earn many more times than any of these companies.

TCS, InfoSys, Wipro, Reliance.. Hello !! you reading this.. take a chance to grab the most, like you people have been doing for long.