It's funny that people see it as a battle. That's a bit dramatic for my taste. They are just two different things, and they both are better at certain types of things.

2D is more personal, more direct, and I would dare say (when it's done by really skilled craftsmen) more "artful". It requires a higher level of sensitive hand-craftsmanship, and fewer people can do it at the level that is necessary to make a truly breathtaking piece of animated art like “Pinocchio”, “101 Dalmatians" or “Sleeping Beauty”.

CG is slicker, more detailed, more modern, but much less personal. It takes a hell of a lot more work to make CG feel even as remotely as organic as hand-drawn animation.

CG is a lot more conducive to having visual consistency in a mass-produced feature film, and you can have grander set pieces because of the technology. Directors can also stage it more like a live action film because it's easier to adjust elements that have already been created.

In that way, CG makes more sense as a business model to a large corporation. You can control more things, and businesses thrive on their ability to control their elements. This is probably a blessing and a curse to CG filmmakers.