Importance of leadership qualities of a founder

How much does the leadership qualities of founder/s factor in the success of a start up?

We all know that most of the startups are founded by whizkids. And not all of the startups, even those with good ideas end up being successful.

Could it be because some of those whizkids lack the leadership skills necessary to nurture, lead and take input from a talented team to take his/her idea to the next level?

How much does this lack of leadership skills contribute to the failures of good ideas?

Even if a founder gets the involvement of the most brilliant VC's in his/her start up, would it succeed if he/she gets stuck up on his/her 'brilliant' idea and does not consider input from them?