It's nothing to do with time, it's simply that he's trying to do exactly the same thing despite the fact that it's failing because the thing he's trying to do suits less players than it doesn't. Time doesn't make McGrath a hard working number 8, nor Clarkson. You say that we first need to see a style of play, but this is it. His style of play is centred around the number six taking the ball from the defence and going direct, with the two midfielders winning the second balls and quickly "recycling". He's been doing it since January. It hasn't worked this season because Ramadani isn't here. Our successes this season have all come when we've done something different (the RC home game had Barron and Shinnie sitting with one ahead - McGrath then Clarkson). We passed the ball through them and that had the knock on effect of bringing Duk into the game. So we already have the answer to who plays where if we're building through the midfield, it's just that isn't Robson's style. His style hasn't worked yet this season because the players don't have the correct attributes to do it (not something that can be taught in a season). He can either keep throwing away points until January by persisting until we get someone in that does have the correct attributes, or he can change it. I have been very quick to praise Robson when he gets it right, and I think it's correct to be critical when he reverts back to his previously failed plan. I find it bizarre that he didn't just stick with what worked. It's a weird form of dogma to have - an ideological belief in a particular formation. It's almost like he sees himself still on the pitch and the number six role would have been something he'd have thrived in with his passing ability, and so he's desperate to see it succeed. I recognise that's a fair bit of a leap on my part, but I struggle to think of any reason for such wilful blindness.
Specifically yesterday, though, it was interesting to watch it in action. Shinnie was far too far forward and when the defenders were inevitably easily winning the long balls, they were getting distance on the headers that just sailed past Shinnie and McGrath. That meant they were both coming from behind the play to win back the ball and thus expending a lot more energy and often isolating Barron. Shinnie, especially, needs to be facing the way he's supposed to be heading and driving forward and the game just largely bypassed McGrath, who is just out of his depth in that role. There was basically a compounding of errors which, with a busy fixture list, was the last thing we needed.
Edit: to add, it possibly isn't glaringly obvious watching it on TV, and it possibly isn't glaringly obvious watching it two feet from the edge of the park in the dugout (I've never understand why managers insist on such a pish view of a fitba game). I watch from the RDL, so it's very easy to see the layout of the team and what they are or aren't achieving with it. Those higher up with a side on view would also see it. I'm assuming that Robson has someone in the main stand relaying back to him their thoughts (like Austin MacPhee does for Scotland for example)?