Doubling means rising the price and not shutting down or giving less to some and more to others. The new price may be too expensive for the customer. In this case, the service or the business model is the issue.

An other regulation may be to pay egally all artists per listen with this point regulated as well.

Spotify didn't turn a profit yet. I would be pessimistic on the business model knowing the Majors take the majority of the 70%. Spotify is de facto a monopoly and so the Majors. With a fair price, the issue is to see the Majors quit the service and launch their own service. Spotify would be useless with only the indep (this is sad). They are protecting their money and the Majors. They don't care about the smaller artists.