What's the limiting factor on investment? It's not capital; there's a glut of that. It's not land; outside a few big cities, there's plenty of space. It's not labor; there's no labor shortage. It's not management; there are lots of unemployed managers with good track records. It's not manufacturing capacity; there's plenty of idle capacity and more could easily be built if needed.
It's demand. We're out of demand. US workers are spent out and can't buy more. This stalls out the whole economy.
This is a new thing, historically. For most of history, the problem was making enough stuff. That's now a solved problem. In the developed world, just about anything you can consume can be delivered to your door within hours or days.
Market-based capitalism treats labor as a cost, not an output. (The measured output is return on investment.) As technology progresses, more work previously done by humans is done by machines. This reduces the relative value of labor.
But buying power comes from labor. As the buying value of labor declines (in the US, it peaked in 1973), the whole economy winds down.
We have no clue how to handle this.
An unanswered question: is there another stable point in this system? If wages were forced up above their economic value, by legislation, minimum wages, or unions, would overall economic output increase or decrease?