Really? That's funny. I have bought and sold 7 MBP's in the last 2 months so who would know the market...you or I? By the way, I am referring to the 13" model only.
When you can buy a refurb 2013 rMBP with 8gb RAM and 256gb Flash for $1,269, it is pointless to put more money into a current machine to TRY to get the same performance. You are left with a heavier, thicker, older computer with inferior display and battery life. Also, no warranty.
Realistically, a Samsung 840 Pro 256gb SSD can be had on ebay for $200. 8 gb of RAM for about $60. That is $260 total for the mathematically challenged.
Let's say you can get $800 for your current machine. Would you rather have your old current machine with no warranty for essentially a total of $1,060, or a brand new current model that will stomp your old machine in every category for $300 more with tax. Most people pay a few hundred just to get a few extra years of warranty with Apple. In this example, you get a retina display, flash storage, current tech, longer battery life, lose weight and thickness, and a warranty for a few hundred. This seems like a no brainer.
so the OP has a 15", I and everyone advising the OP to upgrade have 15" and now the discussion is about 13" just so your post makes any sense?