Ryan: what am I missing?

First off, I'm no political scientist.  In fact, I'm becoming more and more disaffected as I age... or mature.  But, Romney's choice of Paul Ryan as his running mate is interesting.  Romney has run a generic campaign up until now.  Picking Ryan was a fiscal statement.  Obama's camp's excitement about the choice seems to say it all.

To me, it seems a repeat of the 2008 McCain campaign.  Sarah Palin is a woman, but she in no way encouraged moderate voters to move right.  Ryan seems to be a more savvy and intelligent politician, but he seems that he'll have the same effect on moderates: either none or negative.  It seems that Romney is putting all his eggs in the Wisconsin-recall basket.  He hopes that people will be for strong leadership willing to make tough decisions.  Don't get me wrong, I really like the Republican governor in Wisconsin and that style of leadership. I hate the tyranny of special interest groups. But, we shall see.

This is what I don't understand about politics: why is there a trend towards the fringe instead of a move to moderation?  Plenty of rhetoric exists to talk about the two parties working together, but it seems the reality is always to polarize.