The competition is catching up, the HPs we buy cost half of a MBP and frankly, look quite OK compared to the plastic crap of yesteryears.
I'm curious if you think those HPs will last 4 years. I think it's a testament to Apple and computing in general that it is becoming normal for a computer to last 3-4-5 years, and be completely productive. My MBP is a mid 2014, and works fine for all of my development tasks.