It would be nice If this didn't actually matter now that RAM is so ridiculously cheap, but I imagine it's an easy resource for Apple to milk the customer for on optional upgrades and will be for a long time.
Oh, you'd like to upgrade from 1GB to 2GB in your new Mac? That will be $200.
It's $200 per marginal 8GB, actually. Per 1 GB, that's only a $20 markup over fair market value of the RAM. It's not so much when you say it that way, just like a text message is only 10c each, for each of the thousands Twitter/AIM generates.