I can't say for others, it is their money and if they are happy to pay over and above it is their choice. In my case I waited six months (booked end July, got car in early January) but did not pay anything over and above the factory price.
Even if I need a car desperately that it is oxygen for me, what I would do is to add this money to buy an up model which are normally available readily.
For example if I go to buy Gli which is for 1,529,000 if we add 135,000 on money it becomes 1664000 while Gli auto with 1.6 engine is available for 1,679,000 so why not get that? Same goes for other model.