The problem with large companies like EA, Blizzard and Valve is that they are quite happy to consider a particular casual/indie game to add to their catalogue in some form but when they do it stops becoming an indie game (obviously) and may as well drop it's Casual tag as well.
Take DotA for example, it was just a mod and now Dota 2 is being developed by Valve you can bet your ass it's going to retail at the price of a regular game.
On the other hand, Plants versus Zombies is still very popular yet hasn't been adapted into some bizarre 3D engine based game where you have to terraform an alien world using the powers of your army of sunflowers whilst being attacked by zombie models that are worthy of the silver screen in Plants versus Zombies 2 *cough* don'teventhinkaboutitEA *cough*
And let us not forget Angry Birds - such a simple, casual game with a few paid addons, loved by millions (billions?). You watch what happens when that damn movie hits the screens, there will be Angry Birds clothing selling at more than your average tee, Angry Birds 'official' toys that you have to sell a kidney to afford, and then it will just get stupid like Angry Birds toothbrushes and panty liners.
Disclaimer: I actually like Blizzard and Valve as developers and this isn't a dig at what they produce, as they roll out some quality games, but the whole "see something doing well, buy rights to it, change it so it's barely recognisable and make a crap ton of profit off of it" attitude needs addressing.