What are the reasons for cereal companies to change the look of their Cereal Mascots?

When I was younger,cereal characters looked a little different then they do now. Frankenstein from the Franken Berry cereal looks different, so does Boo from erry. The Cocoa Puffs bird is different, and there apparently seems to be a General Bird. The Honey Nut Cheerios line has a whole series of stories with villains, making it seem like the Bee is Superman and the Honey is Lois Lane. The Flintstones characters now look more like claymation in the commercials, and a weird doctor guy has appeared out of nowhere. Honey combs lost their mascot, and now it's all about big mouths, WEIRD! Apparently the kids in the Trix commercials look more 3 Dimensional, and the rabbit now just looks flat. The Froot Loops bird has three nephews, it's like he's Donald Duck or something!What happened to the Apple and Jamaican Cinnamon for Apple Jacks? Is that cereal even around anymore? Why is it that movie/character generated cereals taste HORRIBLE! The cereal for POTC tasted NASTY! What happened to the prize in the box? Is Kellogg's only doing that now? Is it reduced to online codes for all the other companies? And just a random question : Why is the Cracker Jack prize now a paper pencil topper or a tattoo WTF happened to the rings or other cool prizes that were there that were actually FUN?