IMO, this is a fairly simplistic view. You're assuming that highly competent and intelligent people don't see the forces at work which create and exaggerate these different situations.
I lean libertarian because I see all of the problems that come from federal level programs trapping us into a status quo that we are mostly powerless to change. You want to change the way that healthcare or education works...let's just say in your county of residence. It's virtually impossible, not because we lack smart people with better solutions but because the money for healthcare and education is already tied up.
Wealthy people can afford private schools or alternative approaches to healthcare if they want. The rest of the population is stuck with what they are given, whether they want it or not.
I don't know anyone who is happy with the state of public schools in the United States: teachers, students or parents. We're all mostly powerless to change it though.
It's not a lack of humility that creates these views, it's empathy for people who are stuck and want things to be better. I lean libertarian because I see the effects that are making it harder to improve all of our lives.
I simply want to reduce the barriers between a person having an idea of how to do things better and trying that out with other people who agree with them. If it works, it will be imitated and improved upon. If it doesn't, it will be discarded. This type of experimentation naturally leads to constant improvement.
People need freedom to make their own choices without having to ask for permission.