Fixing the car by mechanic vs dealer shop

When our car’s power window wouldn’t shut down, I brought it to the dealer’s shop. They have the original parts so it is the best, I think. When I was given the quotation for $600 which is exorbitant, that made me cringe. Just for the window huh.

I brought the car to a friendly mechanic who said he can fix it. For only $40 that the mechanic charge me the window was fixed and working perfectly. I wonder why the dealer’s shop charges that very high price.