You can get your credential in 4 and a half years.
Yes, if you go to school for Art and then decide you want to teach high school english, you are a little more fucked than those who enter college specifically to become a teacher. But that is true of anyone who goes to college for one thing and then decides to do something different.
Anyways, yadda yadda, I mostly agreed with your original post and while underfunding is a real problem administrators and cronyism, poor teachers with tenure and not enough support to good teachers from the union are just as big.
Still, schools need more money, there simply isn't a way out of the problem or administrators unless massive reforms are made, and they will fight to the death to keep that from happening.