EDIT: as far as the pic, focus on the right
side...the BEST scenario. Several implementations
including Core, and no one group in control of
Bitcoin!
Though that would only make sense when all clients would work on the same blockchain. For sure that will only be the case for a certain time. Though until a fork happens, depending on the setup of the clients, it might be a good idea. They would work on the same blockchain but clients are coded by different groups.