The salary reflects the value of the job to the organisation. If the labourers cannot fill their needs on a salary of QR 600 then why come.
If the organisation start losing staff, who is to blame and should take the stick (certainly not the labourers). If the organisation isn't profitable who takes the stick?
Do the labourers have things on their meind when they finish work everyday? I doubt it.
If they can't manage on QR 600 then they either shouldn't have accepted the offer or need to move. If they could save as much in their base country then go back.
Private organisations have to make a profit, QP don't, that's why the pay in QP is so much better than in the private sector (but only in some fields)and is also the reason for Qatari national staff being reluctant to work in the private sector.
On the topic of the survey itself. I think enough people have commented on the size of the average salaries being quoted and I for one don't believe them. I doubt if the figures have been confirmed.