In any control system that is functioning properly, the methods used to control a signal won’t be correlated with the signal they’re controlling.
Worse, there will be several variables that DO show relationships, and may give the wrong impression. You’re looking at variables A, B, C, and D. You see that when A goes up, so does B. When A goes down, C goes up. D never changes and isn’t related to anything else — must not be important, certainly not related to the rest of the system. But of course, A is the angle of the road, B is the gas pedal, C is the brake pedal, and D is the speed of the car.
In the past, GDP and resources use have always been tightly correlated. But this is just drawing a line through some data — it’s not based on any deep theory. And in fact, these correlations can change very quickly. Just as one example, here’s energy use versus GDP since 1949.
If you were sitting in 1970, you could look at this curve and claim, very confidently, that economic growth requires concomitant increases in energy use. And you’d be wrong. Because the trend is your friend til the bend at the end.
I’ve been looking at this chart a lot over the past few weeks.
It shows us that print ad budgets were doing just fine all the way though the first decade or more of the consumer internet. There was even a little spike upward for the Dotcom bubble. Then the financial crisis and recession of 2008/9 caused a step change down, but when the crisis was over the budgets didn’t come back. Instead, the market had been reset, and budgets have been falling steadily ever since.
You might call this the Will E Coyote effect - you’ve run off the cliff, or the cliff has disappeared from under you, but there’s a brief moment while your legs windmill in the air before gravity kicks in. It can take a while for the inevitable to happen, but then, as Lenin pointed out, you get a decade of inevitable in a week.