It DEFINITELY varies by industry. I’ve worked in industrial markets with dev cycles of 2–3 years for customers with 20–30 year equipment lifespans. I’ve also been in the smartphone platform business with carrier release deadlines each quarter.
I’m also going to have a conniption fit if somebody does the whole “slow moving industries deserve to die” thing. Not everything fits on a little smartphone screen. And not every brilliant product comes out of Silicon Valley.