It is not a "belief" because they are cheaper. Everytime this topic comes up, a bunch of Ph.D's are shocked, SHOCKED! to learn that there are companies abusing the system and to learn that Infosys, Wipro and Tata are the leading H1-B Sponsors with an average salary of ~$73,000
http://www.myvisajobs.com/Reports/2015-H1B-Visa-Sponsor.aspx
One of my friend was recruited by Tata in India, and then sent to work for Citibank in US. His visa was sponsored by Tata, he gets his paycheck from Tata ($72,000), but he works for Citibank in their office. Citibank pays Tata more than the market salary, and Tata's business model is arbitrage. Citibank could directly hire him at market salary and cut off the middle men.
They are not just abusing H-1B, but L1 visa too.
Also, they probably have several other considerations in this matter: - Get the work experience of working in a different country at a client location that means more responsibility, more learning, etc. - Get the option to travel and explore another country, and the job salary covers for the expenses.
Now, usually, the role and responsibilities are that of a technical or functional consultant. But they are not an individual employed directly by the US company. Their employer, one of the above mentioned companies or one of the several ones out there, is contracted.
Note that I haven't worked here in US at any company while being an employee of a consultancy.
I believe that the US based company where the individual works might be charged at a higher hourly rate but only a certain percentage of it makes to the employee and thus they may have lesser salaries. I would love to have this belief clarified, if anyone has any input.
All that being said, I agree that the abuse of H1-B sucks. Though it is all too common outside the bay area. Haven't come across any instances here yet.