Soundcloud needs to come up with a business plan. Right now they only have two money making options: Pro and Pro Unlimited, both which are overpriced IMO.
What they should do it make a single Soundcloud Pro option at $5 month while getting rid of Pro Unlimited and code in a way to sell multi-format music much like bandcamp does so people can buy the tracks directly from Soundcloud and take a smaller 10% commission on it. Have it setup so that only people who have Soundcloud Pro can sell music on their service so they make their $5 guaranteed and then 10% of sales on top of that which is more than fair seeing as sites like Bandcamp simply ask for 15% with no pro fees. You'll see a ton of people subscribe instantly because of the low price for being able to sell music on their site and use Soundcloud without the restrictions they have in place currently. With as many people as there are that use the site now, 40m would seem like nothing.