It isn't that they can't see the solution. It's that they can't see the problem. They can't see the problem if they are looking in the wrong place. They can't see the problem if they have blinders on - for 'none are so blind as those that will not see'.
Gilbert K. ChestertonA fad or heresy is the exaltation of something which even if true, is secondary or temporary in its nature against those things which are essential and eternal, those things which always prove themselves true in the long run. In short, it is the setting up of the mood against the mind.
Gilbert K. Chesterton