I bought a Mate8, about 4 months ago. Why didn't I wait for the Mate 9? Because I can't see paying 600 dollars for a phone, no matter how good it is.
I ran a Mate2 for close to 3 years. Very stable phone. GREAT battery life. When the Mate8 came out in November of 2015, I was looking forward to it, but the price tag (around 600 dollars) I said no. When the Mate 9 was released, the price of the 8 DROPPED to around 440 dollars. The faster processor & dual camera were no concern to me, as the jump from the SD400 chip in the 2, to the faster chip on the 8 was a speed boost. The camera on the 2 & the 8 were good enough for my use. Anything I really want to capture, I use my Nikon D7200 anyway.
If people want to spend 600 dollars, upwards of 1,000 dollars for a phone, hey, more power to you, but, to me, it's just not justified. Each year, faster and faster smartphones come along, but at what benefit? Other than benchmarks, in the "real world" not much benefit. A gimmick/novelty here and there, and people pay over 1000 for them.