The means of consumption comes from the buying power of consumers. Instead of all the productivity gains going to the wealthy owners of capital, they need to be shared with workers. In fact the optimal (total GDP) and stable long-term solution is for worker compensation to rise at the same rate as productivity increases, same as profits. This is in aggregate of course.
When profit gains outstrip wages, you end up with an excess of capital, looking for something to "invest" in. Since production and consumption are lagging, the excess mostly inflates the value of assets, like RE and stock, and precarious financial instruments. This is an unstable situation, and the cause of the GD and collapse we saw in 2008.
The changes to policies that started ~1980 have mostly allowed the oligarchs to take a bigger share of our economy, while still avoiding a crash. They are leaning hard on debt and finance to keep the ball rolling... which is obviously a transient thing... not sustainable. They've also gone global, allowing them to profit from the rise in consumption in developing countries. The US made China what it is, BTW... and Japan before that, and S Korea, Taiwan, and a bunch of others to a lesser extent. Their fast rate of growth came at the expense of the US middle class.