I never really understand this. I mean, if it was just a question of doing a really hard pre-season surely everyone would just do that? It's not like it's a trade secret or something. I suspect Melbourne are actually doing lots and lots of things right, it's just that the ones that involve working really hard get noticed because that's the kind of thing fans (a) understand and (b) put most weight on.
The other thing is, presumably Blore did at least one preaseason with Penrith - I know he didn't play first grade there but he was in their setup aged 19-20 so would have done preseason. If that was also much less demanding than Melbourne it suggests to me how hard you get worked in the preseason isn't actually that much of a guide to success, seeing as how Penrith seem to have managed to be competitive in recent years.