^^^ Well if they aren't in the same genre as you said, then how could they be considered competition for each other? It doesn't matter how long it took them to become huge, there are many artists that were huge when they came out, and couldn't maintain that success for the duration of their careers. You can't predict the future with 100% certainty.

And Prince and Michael were considered serious competition for each other, considering they both made genre-defying music and were targeted towards the same audience.