It may be but it isnt always necessary that only the winner will benefit. The best example is Naresh Iyer, a discovery of A.R.Rahman. He was chosen from the relatively low profile Super Singer of Channel V and not from Indian Idol. Though winners from Indian Idol have not got major breaks as such, Naresh Iyer who was chosen by A.R.Rahman went on to sing some of the fantastic numbers in Rang De Basanti like:
Paathshala,Rang De Basanti
Roobaaru,Rang De Basanti
Tu Bin Bataye,Rang De Basanti
Paathshala(Remix),Rang De Basanti
Incidentally, Naresh Iyer was not even a winner in the Super Singer competition .