Two words: market saturation.
They risk overproducing for the sake of maximizing immediate profits. In the long run that model will not sustain. One of the main reasons Sideshow is popular is because how their items are actually collectible as proven by ebay. Sure those sculpts sure are pretty amazing, but you would not see this fast increase in popularity without the aftermarket prices telling you is okay to buy a $400 statue without the ability to get your money back and more. You don't quit collecting legos, action figures, mini-busts or whatever to dive head first into something that will lose you money. I don't care how pretty it looks on your shelf.
Sideshow uses the excuse that the hobby has grown and their user base has expanded. Sure, that's certainly the case and a true statement. However, they still need to keep some kind of control on the core of what your business is: collectible items. The open edition discussions pop up in just about every thread. A lot of it has to do with budgetting and planning to be able to bring these pieces home. A lot of the complaining is from people that want to support Sideshow and not just bash it. The limited pieces get priority over open ES. That's just common sense to avoid paying more later. That's basic economics/budgetting but the way Sideshow is acting is like it's a free for all and we may even trick you and turn it into open ES when you are not looking. Buy it if you like it. Edition sizes be damn. Collectibility be damn. True fans don't hesitate.
That's the name of the game now.
I understand that Sideshow is a company and want to maximize profits. Okay fine. Overcharge a bit and increase the ES for popular characters like Batman, Superman, and Hulk. But don't get greedy and think you can abandon what you're company represents: a collectibles market. Open ES? Come on! When you oversaturate the market with product and lose the intrinsic value of what a collectible is, you will falter. Your collector customer base will stop buying. These are, after all, just big cool statues. They're not a necessity. And certainly, they're not worth $600 without the inherent factor of being a limited edition collectible. Whether that mean 1000 or 2000. So long as there is an ES.
And another thing: what is up with first saying a statue is limited (Galactus) and then making it open ES?! WTF. Have some integrity.