Teachers Unions

I've had some pretty great teachers. I've also had some pretty miserable ones. With the (seemingly) increased militance of teachers unions making unreasonable demands/comparisons and from purely anecdotal evidence, I have been wondering if the latter has been flourishing more than the former. Is the economic power of the US (and Canada) in spite, rather than the result of our education system (and as a corollary, teachers and their unions)? Apparently Steve Jobs and Michael Dell (both on the same stage no less!) think so.