My 2011 MBP is still my primary. This is the case for a lot of people because the newer versions just don't compare. On to of that you can't even upgrade the components in them since everything is integrated into the board.
In my opinion the best user friendly mac was the unibody early 2009 15" MacBook Pro.
It was the last Mac with a removable battery.
Plenty of technological improvements have been made since then but I still love that model.
Ditto. My 2011 MBP is a truck that just won't quit. Although I've replaced just about everything in it but the processor, the fact that I was able to do so makes me love the machine.
We currently have two 2018 MBPs on the shelf that were bought as 'upgrades' back then but they're sitting unused because people are sticking with their 2015 MBPs until they won't be maintainable anymore or Apple (or someone else) releases a version that's an improvement over 2015 MBP instead of a downgrade.
I'm also on a 2015 model, but it was manufactured in early 2017 so it's not that old. I and several people I know are holding out on the 2015s for as long as they can because of ports, no touch bar, and a better keyboard compared to the newer models.