<<< musician would be considered to be self employed >>>

Not necessarily. This is where a good knowledge of business is beneficial. It's never how many dollars you make, it's how many dollars you keep. The tax system favors those who know the multitude of ways engineered for the knowledgeable to keep the most possible of the money they garner from all the available methods to bring in income. One can become a millionaire walking dogs if they understand business and work toward the goal of earning a million dollars. So can the average musician. The product is irrelevant if one can figure out how to sell it. It can be a product or service. The relevant point is to retain received income and to generate multiple streams of income.

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