Climbing the rungs of the ladder to the top might be judged to be about education, ambition, risk, effort, authority, independence, who you know, who you can push out and how much money you can make. But, leadership under God's paradigm is something very different. It's defined by responsibility, faithfulness, sacrifice, service, dependence, courage, boldness, obedience, holiness and good character. The emphasis in this passage is primarily on holiness.
Leaders are held to a higher standard than their followers are... or, at least, should be. A leader is rightfully expected to do better. By the natural scrutiny that accompanies a bishopric, a leader is limited in what he can... or should... do. Likewise, the glass house that spiritual leaders live in makes it reasonable that God would limit who can serve in the office... which, of course, is exactly what He has done (see Acts 6:3, Titus 1:6-9, I Timothy 2:12 & 3:2-13). Now, I can't imagine that any man could honestly declare himself qualified by God's standard - so, that responsibility falls to the congregation as they adhere to the Bible and to the Holy Spirit's affirmation of it.