Those Westerners getting 35k+, Villas etc are most likely working in the oil industry. Oil price is over $100/bbl. There is a severe shortage of experienced people in the oil industry due to older folks retiring. Hence the high pay - not just in Qatar but all round the world.

I can also tell you categorically that highly qualified Indians - ie those from IIT or similar - are getting equally lucrative packages all around the world.

So to be clear these large salaries are for highly skilled specialist, usually from top universities, working in a sector with huge demand.