My intuition tells me that productivity per capita has been increasing; we have not been relying on population growth alone to grow the economy.

The catch is that the increased production is not distributed equitably. For the average (more productive) worker, the things that they need such as health and housing are not any 'cheaper'. So where is their 'share'?

As productivity increases, credit expands to capture it. This is how, ultimately, those with the capital end up with the increased productivity.

Just a thought.