Worked before
One thing we do know is that Supply Side Economics has been a failure
Supply side was not invented in the 1980's . From the days when the settlers traded with the Indians, that was supply side.
All those little frontier towns were examples of supply side working the best for the most.
And it continues today...
For example. Downtown Tampa.
The city proposes a site to build an entertainment and sports complex. This area was blighted and needed improvement.
Once the plans were publicized guess what happened. Land near the site became a hot commodity. People started buying the land. They built businesses and housing.
A friend of a friend bought this old run down sport bar. He took his own money and that of investors and borrowed from banks. He turned this place into a successful sports bar. Before and after every event held at the complex, his place is packed.
The loans were paid, the investors made a profit. Over 100 people are employed at the place. Not only that, there are dozens of newer businesses in the area as a direct result of the private investors who had a stake in the Complex.
So lots of new jobs were created. A once blighted area of the city is not a viable business and entertainment area. Once crime ridden and filthy. this is an area known for safety and security as well as prosperity.
So, you tell me, where's the problem with supply side?