There is nothing wrong with admitting failure - it is one way to making sure you improve in the future. But when the manager goes on about 'fine margins', he isn't admitting failure. He is implying that if only we had the rub of the green, the decisions from the ref or the wind blowing in our favour then the result of the matches would have been different. And if that is the case he doesn't need to change anything as there is little wrong with the underlying tactics, formation, skills or attitude of both the players and himself , so - as we have seen all season - we get the same performance rehashed over and over again. Occasionally it succeeds, most of the time it hasn't.
I don't think Robinson admits to failure - even in the light of the league position in relation to his supposed/presumed budget - and that is where a large proportion of our troubles lie.