When was Campbell first made captain? If, as I suspect, it was in the late-1990s, then the regular turnaround of managers during that era wouldn't have helped his chances. Hoddle managed for 3 years, Keegan for 18 months, Howard Wilkinson and Peter Taylor each had 1 match as manager (maybe 2 now...
Rather a strange post really. Phil Neville's level of blame to Manchester United's current league position is quite some way down in the food chain behind the players, David Moyes, Ed Woodward, Sir Alex Ferguson and the Glazers.
Also, in your comparison with the Nevilles, you also fail to...
Wasn't a bad captain though, was he?
That happens all the time in other countries. They pick their best player to be the captain - Zlatan Ibrahimovic and Cristiano Ronaldo are 2 current examples. To my knowledge, neither had captained any of their clubs previously either.