Because pissing your consumer by forcing them to buy outdated overpriced hardware isn't a so good idea in the long run.
I buy the 2015 because my MBP is my working machine and that my 2011 MBP had already done to repair twice because of dGPU pb (At the times the problem appears in late 2014 I had to got it reballed because Apple was saying there were no pb with the dGPU and I can't stay without my computer).
Where I lives an entry level MBP 15" cost around 6600$ (yes, you read it right).
Luckily I travel to Europe twice a years where the price are more affordable. So knowing that I'll return in January 2016, when I went there in 08/15 I decided to wait for the October update. But it didn't came.
So I planned to buy the 2016 MBP in in 08/16. You know the rest of the story: I am paying 3200€ for a more than one year old hardware.
So, why I am buying? As I wrote earlier, I use my computer to work and I can't change all my workflow and buy all the licences of the software I am using like this. Right now I HAVE to stay with Apple and I HAD to change my computer (mainly because of the dGPU problem...). No choice.
So Yes, I am pissed. I have an apple TV, a MacMini, 2 iPad, 3 iPhone, a MBP11 (an now a MBP2015) and was planing to buy an apple watch.
But now, what I am really thinking is how I will change my workflow in the futur so I WILL NOT depend of Apple again.
And as I am thinking to move from the Mac, I am also think if it won't be interesting to move from iPhone to a Galaxy edge next year (I really liked the function of edge and the screen is gorgeous). And if the android tablet sync well with an android phone, I will not see any point to buy an also overpriced iPad.
And taking all of this consideration, I will not recommend Apple so fervently anymore.
So yes, it was a dumb move from Tim and it's team. Loyalty and trust are hard to build.