Tony,
it depends on the water......pike do get eductaed and on waters that are well covered by lures the fly will outfish them, provided the person can wield a fly rod effectively.
The difference is any foll can pick a spinning rod up and cast a lump of metal out and wind it back, even give a few rod tip twitches.....give that same person the fly rod and they might not be able to get a line out two rod lengths.....doesn't mean the spinner is better than the fly.
You are at NO disadvantage using a fly, in fact you have a very large advantage, and that is the movement within the materials in addition to the movement of the whole through the water.
You want to combine the two? How about a spinning rod with either a controller float, bubble float or Bomber float (seatrout in Denmark) and put a fly behind it....just don't call it fly fishing, because it isn't, it is fishing with a fly. An entirely different thing altogether, but it allows you to place a fly in those places a spinning rod is more convenient and without resorting to agricultural ironmongery. Don't get me on to rubber lures.