But what if you want to sell a product you designed but can't afford to create it or to setup a factory for it, so you want funding, so you try to get investments, maybe by selling equity in your company. Is that not valuable to society? The people that take the risk that your product may not sell?

That's where small business grants from the government comes in.

Helping people thrive without being beholden to ruthless opportunists or run the risk of bankrupting private investors is EXACTLY the kind of thing tax dollars should be spent on in stead of the MIC, subsidies for the most profitable corporations in the world, and other such enriching of the already rich.

This is mythical thinking. Frankly, there's just not that many products that need inventing, particularly that need a factory. We are past the era where a revolutionary bread slicer will change society. Most of the actual advancements we are seeing come from grants into general scientific research. Not from some lone Einstein with a vision.

What actually is happening is some of these discoveries are very good and they ultimately get scooped up and patented by some corporate entity that thought the research was marketable.

Recognizing that reality, that innovation basically never comes from the founders of a company, should really lead you to understand what's broken about the US economy.

How did anyone do anything before currency was invented?

Your comment implies that what you describe is a requirement for a functioning society

It isn't.