You would still need a special screwdriver!
It‘s true that Apple use the fastest RAM they can get their hands on. And if I’m being generous I could say that they own the design and they might have tuned the hardware to only work with certified RAM specifications, which would effectively rule out letting wide boys plug in any old memory. The price of RAM is also quite volatile and there is a theory that Apple negotiate a price for years ahead, at some cost.
On the other hand, it’s easy to argue that they’re just profiteering plain and simple, because that’s what their target market will put up with. You won’t find a cheap Rolex, for example, even if the parts are super cheap. Rolex know their particular customers will pay a premium price day or night.
i‘d like to see someone asking Tim Cook this question in one of his Q&A sessions