Its probably a little of both. Majoring in education is probably as low on the motivation scale as one can get, except maybe for journalism. So it probably attracts slackers and those with arrested development. There is also the fact that teaching is an automatic membership into the government club of unions, tenure and automatic raises with little chance of termination, even for egregious behavior.
Yep! And it is a real travesty because teaching used to be such an honorable calling and it still for those with a true calling. Unions, in particular, have been a major cause of the ruination of this nation.