except they charge you for the processor on top of the cost for RAM.
Probably a business opportunity here, sell high RAM machines at a smaller markup. You could probably sell a 96GB RAM server for half the cost, of what others charge and still make a hefty profit
They charge that much because there's a demand for it and people will pay. Dedicated servers are a smaller market, so no one is eager to charge less than X amount for renting a server.
However, 8GB-16GB of RAM is a lot and also makes the motherboard a lot more expensive (and Windows slightly more if it's a Windows box, 64bit). If you can put together your own machine it doesn't need to be super expensive.