So, to make the bar attractive, the owner plays music, and people come from all around to listen to the music as they drink.
Now, why exactly is the bar owner entitled to this increase in business brought about by the musicians?
If I ran a coffee shop, and people came to my business to read, would anyone have any problem with me running copies of all the latest best-sellers and providing them to my customers?
Bad analogy. You buy a book, you dont buy the right to copy and distribute it. I buy a CD, or turn on the radio which I have bought, I am entitled to play it. As long as I am not (directly) charging people for the performance, then there is no problem. Any profit the establishment makes from the music being played should be offset by the exposure the music gets to potential purhcasers. This isn't the same as making copies of a product and handing it out for free.