This is the major issue though, during the years that Bottas has been at the team there hasn’t been a single point in time where anyone has ever really felt that Bottas has the making of Hamilton. Flashes of brilliance here-and-there, the odd weekend where he is almost untouchable (Suzuka last year spring to mind) but the relentless pressure you need to break someone like Hamilton has never been there.
Not to say that he’s alone in that, far more successful drivers than Bottas have tried & failed to find that recipe, but it’s no small coincidence that during the 13 full seasons in F1 he has only been beaten by his teammate twice. Between the Austrian and Styrian races, whilst Bottas went off on a jolly down to Monaco, Hamilton stayed at the track and spent three solid days with his engineers going over everything in detail to extract every drop of pace he might have missed in week one and he ended up giving the whole field an education almost all weekend. This mentality is what separates the good from the great - in all forms of sport, not just F1.
Perhaps if “Bottas 2.0/3.0” showed that level of application, Mercedes might have to make a call but, as of yet, they haven’t ever needed to.