This may not hold with today's youth. There's theories that people identify with the political party of their youth (much like they do with music) as they age. This is an alternate explanation for the increasing conservativism of older generations in the US that grew up during Reagen years. For nearly 20 years conservatives ruled and this lines up with the formative years of today's pensioners.
Another theory is that youth are not going through conservatizing life events like marriage or home ownership because they've been screwed by so many economic disasters. It's hard to argue against this theory, the question is how much of an effect this will have long term.
Yet another theory is more obvious. The anti immigration and anti gay policies of conservatives are wildly unpopular among those under 45. Some estimates I've seen are that less than 25% support either. The younger generations are also less religious, more urban, and more ethnically diverse. All traits that tend to increase left leanings.
I personally doubt school had much of an impact. Educators have been left leaning for centuries. I think it's used as an excuse by the conservative party in the US unwilling to admit their policies are unpopular for more based reasons.
I agree with you that deficit spending has become bipartisan. The fiscal conservatism that once defined Republicans is more of a libertarian aim now. Again I think this will play out in an interesting way. Without fiscal conservativism the Republicans are left with religious and cultural conservativism which are both wildly unpopular among younger generations.