So, it's probably wise for Apple or any other company to keep a model or two that are modular to satisfy the geekier crowd. It would be expensive, because with larger-numbers, the razor thin laptops will be cheaper due to scale.
A year ago, I wasn't sure how much longer my ancient (but still functioning!) 2008 MBP would be going on. So I went shopping. Found the same tradeoffs Marco mentions here: I didn't like the sealed nature of the newer offerings (and also, AFAICT no screen density can make up for the inexplicably missing matte displays).
I ended up buying a used 2.6Ghz i7 8GB 15" matte MBP instead of anything new from Apple, though.
About the only complaint I have is that Mavericks seems neither as stable or as well-performing as Snow Leopard, which seems to be the last time Apple released an OS that was a strict improvement over previous releases. Too bad it's no longer safe to run given the state of updates.
I still have my late 2008 MacBook Pro--the first 15" unibody design with a Core 2 Duo. I just spent about $250 for 8 GB RAM upgrade and a 500 GB SSD and did a clean install of El Cap.
It actually runs faster now than it did with the stock HD and Mountain Lion! Granted, I'm not doing a lot of heavy computing with it. For web surfing and the basics it still works great.
