However, a logical scenario is the 6 Pains approaching and attacking Madara from several directions so that they can not all be taken out by a single attack. Again, I am not saying they woud definitely win but big flashy attacks are like say a nuclear weapon which is not ideal in a one on one battle. Right now most of what we have seen from Madara is the big flashy attack against groups of enemies concentrated in a single area.
Put it like this, if you play role playing games like Mass Effect, there are characters that are better at crowd control and there are characters better at taking out a single enemy. I have no doubt Madara excels at both but I have seen more evidence of the former than I have of the latter. And I haven't seen examples of the latter that far outstrip what Pain, Itachi or Obito can do in a one on one battle.