How come code share prices can sometimes vary so greatly? As an example, I took a quick look at prices from NYC-Rio de Janeiro (GIG). Varig flies that route, with UA offering a code share (same flights, of course). When I price it as a UA flight, the biz class ticket comes to approx. $7,300. However, that same flight, booked on Varig, is under $6,000. Wouldn't I get UA miles even if I booked through Varig?
What's the reason behind the drastic price difference?