When it comes to things like starters, alternators, etc most any dealer worth their salt can tell you if there is remanufactured or aftermarket versions available.
Interesting position. This begs the question: If your assertion is that I should support my local dealer, even at a higher cost, to help keep the dealer in business. Since the OEM's also need the profit from parts to sustain their inventories, and their parts network. Is it not then a bit hypocritical, for you then, to suggest non-OEM parts?
Yes, this situation is exacerbated on by the OEM's pricing on items like starters, and alternators. Prices that are often many times that of a similar automotive part. Giving at the very least, the appearance of profiteering. This of course, leaves the door wide open for aftermarket manufacturers, and rebuilders to under cut them.
If you always go to the dealer, and always buy OEM, your going to pay more, and more, as time goes on. And, if you don't support the dealer, and the OEM, they may not be there, when you need them.
My point is, like everything else, there has to be a balance. Then, we can all survive.