I don’t know shit about it, but I’m guessing the ad business isn’t really standalone itself. Guessing it’s the ad service that kicks in for developers that don’t pay for the engine. If that is true, it’s stupid to expect both to be individually profitable. It’s also likely the ad business wouldn’t be profitable if it didn’t have all those indie developers that have it incorporated into their games. Really sounds like a working system just wasn’t profitable enough, and they needed more blood from the stone.