I think this is a common path for MBPs of the same age. I've got a 2009 model and upgraded the HD to SSD and memory a couple of times. The processor can feel a little sluggish but it still handles what I need it to. But that's not really special to macs. Hardware just got to the point where it was mostly good enough. Not being able to upgrade the new MBPs does make me think twice. Either I fully load it and pay the premium or risk feeling I need more of XYZ later.

Something I do like about my MBP, even after quite a few years of abuse it still looks in decent shape. The case, screen hinge and keyboard all still feel solid. Which is where lots of other laptops seem to fall apart. Though the battery and trackpad have seen better days. Something nice about macs is they are usually serviceable for quite some time, either via Apple or third parties - I needed a new power adapter recently and could walk into a shop and get a new one there and then. Trying to track down power adapters etc for short lived models from other manufacturers can often be a pain.

All in all I don't think it's anything magic about macs. If you bought a similarly specd and built machine from someone else you'd be in the same position.