[Z]

Take That could easily carry on as a two piece of Gary and Mark and the music would sound the same; the only value Jason Orange (and the other one) add is just being an extra body to fill a stage - because they're dancers who are now too old to dance and Take That's image doesn't require choreography anymore. Even if Howard announced he was leaving, they could quite conceivably carry on indefinitely just the two of them. If Robbie rejoined they'd be quite a three piece, I'd say.