Well, perhaps because there is no general vision for the Western world anymore. We are flooded by bad news everyday, and social media tends to make a mountains out of molehills, yet the general living standard is as high as it's never been before.
There is no "western world" to lead like it was during the cold war. It all breaks down to the specific problems of the countries, they all have individual problems - at least perceived by the citizens - that the voters expect to be solved. The more content people get, the more they are looking for scapegoats they can put their blown up problems on.
And the problem remaining that affects all western countries - like the situation in the middle east or the terrorism coming from there - are not easily, if at all - solvable with a vision.