That paper has nothing to do with how piracy affects sales, which is hundreds of millions of dollars in sales on iTunes alone. That paper tells us that advertisement usually leads to more sales, which anyone with common sense will tell you. But the problem is the money loss the bands get, when they have to pay the record company. All the extra money from those advertisements will get sucked up by the record company, but the amount of money lost overall due to piracy affects the bands more than anything, since that's their commission essentially that you're stealing.
And you said you wanted all music to be free, but how do you expect 99% of bands to stay in business then? That would ruin the private domain, and then companies wouldn't have to pay bands to use their songs.