This is not to say cardiovascular fitness is not important, it absolutely is for the sport however, a full vault from start to end may take about 7 - 10 seconds, this is strictly anaerobic.
This is true to an extent but my argument with building up a little endurance at the beginning of the season (like max 20 min jog) is so that you will be able to make it through an hour long sprinting workout in the fall. If you take someone with no base, or endurance and start sprinting them, then they will tire out really fast if not black out from exhaustion.
Even if you are not into long sprint workouts (like I said an hour, cuz that is a long time), with no endurance you can't vault for an hour and be able to jump on your biggest poles at the end of the hour.
That is why I see pole vault as an endurance sprint (not that you need to be able to run for a long time) but you need to be able to run your fastest Every Time!
If a sprinter is doing workouts and has to run 10 x 50m, and he gets a little tiard and the last two or so are slower than the first ones then no one reall notices, but if a pole vaulter takes 10 vaults from his full run and his last ones are a little slower.... he bites the dust!