Well, if the analyst projections are correct, the price for SSDs will reach about $1/GB by next fall. It'll take another year (2 years from now) for the price to drop to $0.6/GB which will allow you to get your wish of 500GB SSD for $300.
There's probably a surplus of RAM available right now, due to slowing PC sales, and a tightness of flash supply due to surging cell phone, tablet and SSD sales.
Unless several more new flash fabs come online to bring supply levels above demand we probably won't see a particulary rapid cost reduction there. Even shrinking from 0.3x to 0.2x micron manufacturing nodes didn't have a very large impact on price despite it essentially doubles the potential number of chips (and thus storage capacity) per silicon wafer.
When did you buy 8GB of RAM for 500$? I know apple still charges a ridiculous 400$ on their website but you can get 8GB of RAM for your model of MBP for less than 60$ now.