Sure, a lot of live action stuff would LOOK better and make more sense visually as an animated film or series but, unfortunately, anything that's animated will never get the same ratings as live action. The average adult sees animation and automatically assumes "this is for babies and I'm a grown up who doesn't watch stuff for babies".

I'd also like to point out that animation is not cheap at all. If you want it to look good, it's extremely expensive and time consuming.