So if I am on a deserted island and I demand a burger, it will magically appear?
If you are on a deserted island and you demand a burger it would mean you are delirious.
But if there are others on your island, and if one of them has a cow, and another can bake a bun, provided you can pay enough for a burger to justify killing the cow, and presuming those others are interested in having some of your money, rest assured your demand would be met.
But without your demand, which includes your ability to pay, there would be no movement.
It is not simply about demand. That is the problem with current economic policy. Demand is useless without the ability of suppliers to create products that are demanded. I demand flying cars, but they aren't here.
You may also rest assured that if there were sufficient demand (which includes ability to pay) for flying cars they would be available.
As it is a fellow in Norway or Sweden (I saw it on Discovery Channel) has built a sleek little car with folding wings and tail and a propeller that does take off and fly. How much are you willing to pay him for it?
Capital is not taxes. Capital goods include technology, machinery, and other resources used in the process of producing (rather than consuming) something. People demand consumer goods, which come into existence due to capital goods. On my island, if the technology and tools to create burgers (the capital) do not exist, no matter how much I demand one and am willing to pay an arm and a leg for one, I wont get one.
The point that escapes your attention is
demand for the materials needed to produce burgers.
Capital is accumulated through savings, not spending. Savings are invested into capital production processes. Government spending redistributes what could be saved into spending money, slowing down capital formation and economic growth. Because capital is so valuable to an economy, those who are best at organizing it become rich. Rich people invest their money into projects that increase capital and thus increase the production of consumer goods. Taxing them more and more will not help anything and will only slow down production. Government is not efficient at organizing capital, yet higher taxes give government more money which should be used to create capital (thus allowing for more consumer goods). Higher taxes is never the solution, especially during a recession in which the entire capital structure is being reorganized because of misallocations of it during the boom period (i.e. too much put into housing).
FDR's
New Deal proved your theory is wrong.
FDR imposed a progressive tax on the rich with a maximum rate of 91 percent! The resulting revenue became the
capital with which he financed the CCC (Civilian Conservation Corps) and other federal make-work programs which provided useful employment for millions of Americans made destitute by the Great Depression. This had the effect of reviving the economy and giving rise to many thriving new industries needed to supply the
demands of millions of newly employed workers.
FDR's use of taxes as capital, priming the pump as it were, initiated the most prosperous and productive decades in our history, the late 40s to the early 80s, the era when the American Middle Class came into being.
Then came Ronald Reagan and supply-side economics. And here we are.