I understand the situation perfectly well. The "business first" scenario is like trying to stand a pyramid on its tip. It can be done but is unstable. Following Lincoln's wisdom of "labor precedes capital" is like balancing the same pyramid on its base.
Permitting tax avoidance enables abuses like the "Dodger owner" posited above.
A sales tax won't make goods and services cheaper but it will put more money in the hands of the consumer. Which, in turn, allows the market to determine which producers succeed and which fail.
As to enforcement, let us consider the hot dog vendor: if he does all his business in cash he can easily evade his income tax; his problem comes when he buys a Lexus, Rolex or mansion. The problem for government is policing millions of small income producers.
Now consider the NYSE: Its credibility is absolutely paramount. If they are charged with collecting sales tax on every transaction they'll do it. It stands to reason they would avoid a confrontation with the Feds. In addition, negative tax consequences would tend to reduce volatility.
Hell, if you tax EVERYTHING, collection could become a profit center for truly large businesses. The Feds could allow the NYSE, or grocery stores, to keep a portion of the tax collected as a fee. This may already be the case with state sales tax, I'm not sure.
In the end, it isn't the system it's the implementation. The current system is so complex it is easily abused.