"The mid-2009 Pro was basically the last Apple laptop that let you do all the things that kept it running: new memory, hard drive, battery etc. From that point, Apple started locking the laptop down."
Not quite.
My Early 2011 MB Pro 17" is running almost every day as a desktop machine with external monitor, keyboard+mouse and an Akitio Thunder Dock Tbolt hub that gives me 2 x ESATA, 2 x USB 3.0 and one FW 800, plus one extra Tbolt. The MB Pro itself has an Xpress Card slot for further expansion.
I've myself changed fans on it twice, battery once, HD twice (it's now a Samsung 1TB SSD) and I upgraded the RAM to 16GB. This is a machine that earns the Pro designation.
I also have an MB Air 2013 13" with 8GB which has proved itself capable enough for serious video and audio editing as well as being a handy typewriter.
The new MB 'Pro' is an embarrassing joke. Eventually, I'll also be looking for a new machine, but I very much doubt it'll be adorned with partially eaten fruit on the lid.