What's the point? Pure marketing. It's connected with DJ gig's too, it's not just about releasing music.
Armin's ASOT wants big names on their festivals. So why not make contracts saying: You must release music exlusively on Armada (or sublabels), and then you will play on Tomorrowland and ASOT events, Armin will continue support on your releases.
This way Armin's ASOT has the whole trance scene in a tight grip, and can precisely make it move just the way they want. No competitor that can "challenge" Armin, since all potential challengers get onboard and will be marketed as "big", but not that big
Another example: Trance Energy stopped after 2010/2011 (in 2011 it was called Energy, with more house/edm, but it still failed). Was this purely a move by ID&T to stop with their brand Trance Energy? Or were they forced by the plans created by Armin/ASOT? What choice does ID&T have, when all major trance dj's are signed exclusively to Armada, and cannot perform on Trance Energy? Just look at the roster, all these deejays would never make an apperance on Trance Energy again: Armin van Buuren, Markus Schulz, Cosmic Gate, Paul van Dyk... or newer stars like Rayel, Gareth Emery, W&W, Dash Berlin, Aly & Fila. What choice did they have? It's all marketing and business. ASOT wanted their own trance event, where they can decide everything for themselves. And that is what happened...
Now Armin is guaranteed the main headliner on any mainstage. With fellow label-artists filling the rest of mainstage. Other artists can fill smaller stages...
Music businesssssss.....
This is not just Armin/ASOT though. It happens everywhere. I've also learned that huge names like Tiesto force music events to add other "talents" and put them on a big stage, and good time slot. Tiesto is known for pushing "Mike Williams", which is a youth-dj from his home town Breda. This is an excellent way of creating a star. Mike Williams is now mainstage dj right in front of Tiesto or whatever big name. So he must be good right? Hurray for a new star!
Music business..........
Also fun... track names and versions. This track for example, a EDM track on the mighty Spinnin Records. It's made by "the voyagers". Now, Spinnin said: OK, we will sign and release your track. It's good. But, your track will be called "Oliver Heldens Edit", eventhough he doesn't have anything to do with your track. But we want to promote that name, so yeah... let's go for it? And so it happened. It's called Oliver Heldens Edit, who has 0% connection with it....
Music businesssssssssssssssssssss =D