Think they've explained a few times that it's quicker for them to work on the updates to all the systems internally, rather than trying to merge it with the live game (which includes beta branch) incrementally
So we could have more incremental updates, more frequently, but the side effect would be that all the stuff we've seen, combined, would take a lot longer to get into the game.
As an example (just pure example), all the stuff they are working on now, we get that in september. (Beta branch)
Where as if they did smaller updates of this, we'd get that piece meal, but all the content and changes from the update would first be fully implemented august next year (beta branch)
So we'd get more frequent updates, but it'd take significantly longer to get everything
That's how I've understood what they've explained