[Confusion]

I fail to understand why this is of interest. The number doesn't tell you anything. If only 600M people were alive to today, the number would be a factor of 10 smaller. So what? You can't distill any meaning from the number. It doesn't predict anything, doesn't spell out opportunities, doesn't explain anything. It's a synthetic numerical fact, as constructed and unrelated to anything Real as the fact that the length of my thumb is exactly 1.5% of the height of the Eiffel tower.