Couple of things I'd like to point out...
1.5 million registered users is not the same thing as 1.5 million units sold is not the same thing as players who have paid subscriptions.
1.5m represents the number of registered accounts that were active shortly following launch. Keep in mind that SE reactivated all of the old 1.0 accounts during the ARR trial period. If you had purchased 1.0 and never logged in to play ARR, you'd still be counted among the 1.5m because your account was made active during the trial for several weeks.
2 sales 1 subscription(giggety). There are many players who play on both the current platforms and might possibly plan on adding PS4 when that is released. They've purchased several copies, but only maintain a subscription for 1 account. There are also players who purchased more than 1 copy for the same platform for the purpose of upgrading/promoting SE(standard edition) to CE(collector's edition). Sales are always going to be higher than subscribers, especially being a multi-platform MMO.
SE's financial reports are not just based on the performance of FFXIV. They develop, market, produce and distribute many, many games. From PC to console, phones to tablets, handhelds and browser-based social media games. Movies, comic books and graphic novels? Sure. Toys and figurines? Why not. List goes on...
tl;dr
XIV has come a long way, but it's not the driving force in a 10 billion yen swing. The title of that article makes me want to slap whoever paid the writer... hmmm, wonder who it could be?