1. "iTunes is also the preferred tool for listening to pirated music, which generates nothing for artists."

Spotify has paid out $1B in 9 years. iTunes is paying out over $1B PER QUARTER. [1]

2. Spotify also has an ARPU cap ($120/yr) - Not only do none of their competitors have this, but it is likely others will find ways to increase APRU (better video CPMs or iTunes exclusives are just a few options). This will likely make Spotify a less appealing distribution option going forward.

3. It seems implausible Spotify is the cause for reduced piracy - YouTube has 10x the content, $0 cost, no need to download an application or creating an account and has 50x the user base.

[1] - Don't worry, I'm not including app sales in this figure.