Why the focus on bidding?

Here's a topic for debate:

You are tasked with teaching a rank beginner the game of bridge. They are highly analytical and motivated to learn. Assuming they've played other trick-taking games (spades, for example), what do you teach them first and why?

I'm curious as to how many people would start with the bidding aspect of the game of bridge versus the cardplay... It strikes me that most 'lessons' and 'teachers' are working on teaching people to bid well. However, if cardplay is never covered to an equal depth you wind up bidding to great (though perhaps thin) contracts that you can't make because you give away tricks.

Thoughts?