That`s why for MIL`s cake I made a Rainbow cake (white cake with food coloring in the divided batter) because not everyone likes chocolate , but to make the cake more flavourfull I added a cherry pie filling layer.
I do watch Cake Boss a lot and they do mention often that the cake must taste good as well as look good. The fillings they do seems real good.
Cake Wars is another where they are judge on the taste of the cake as well.
I can`t imagine making cakes for selling as just the cost factor of making the cake is quite a bit. (Granted it would be cheaper in bulk if making more cakes) In the end , I spent $40 at the Bulk Barn just in ingredients and that was making my own Fondant. I can only imagine what someone would charge for such a cake . To have to pay a lot just so the cake does not taste good!!!