Parts quality - factory v.s. dealer/online parts

[Machnumber2]

When they put parts into a brand new car in the factor, they usually seem to last for many years before you have to replace the part. For example, my driver side console window switch looked original 4 years ago when I replaced it. That means it lasted for (2000-1988) 12 years before it needed replaceing. I replaced the part with one from the dealer at a cost of around $70. Two years later, I had to replace it again for another $70. Its been two years again and yet again the switch has failed and I have to replace it. This same story can be applied to many other parts that I have delt with on this car.
My question is, are the parts they use at the factory far superier to the parts that are available to the dealers and public even though they are supposed to be the same part? Sorry if the question is hard to understand but this has been bugging me, would appreciate any input.