The difference being that in the past, transistor budget and power budget doubled every 18 months. It is quite easy to get a large boost when you have wider everything, and deeper everything, and more complex logic everything over the previous generation.
Today, we are seeing what? 15% higher density per generation? .... and even this only after 3 years. Additionally, the cost of going from one node to another is on an exponential curve, so that 3 years may soon look more like 6 years.
I could be wrong, but I think the days of big gains every generation are over for good.