I think closing his own brand relates to the fact that the vast body of his work is consulting and styling for other brands, magazines rather than simply working on the Kim Jones label. He would be really overworking himself if he kept working on his own brand label, did the consulting stuff and Dunhill too.
Personally, I don't think he has closed his label (which could possibly be just a rumour?) because it wasn't doing well. It was because he personally wants to go further than it alone could take him - he is very "business" focused unlike a lot of creatives.
I highly doubt he closed his brand too because it is profitable. I know for a fact though he stopped designing from Umbro, which was a collab anyway no? But expect to see Kim in many more places to come!