kironin

a "blackbelt" could mean as little as training for less than 2 years.
it doesn't mean expert, keep that in mind.

a good friend who has been a karate instructor for more than 30 years could give you story after story of a blackbelt coming in wanting to retain their rank and then getting wiped across the floor. The good ones stay and learn.

it's not the art, it's how you train.

how you train depends on your goals.

I don't talk ill of other arts but I know what my goals are and what I like. When you make a blanket generalization about something that you have not studied you are bound to make an ass of yourself.