"If these rules are correct it doesn't really sound like it pays to fly
DL as a WP member elite member. Why would I fly DL when I can fly NW or CO and upgrade? "

Well, I thought the point of alliance is to expand the route network available to travelers, not to encourage your FF's to fly on competitor's metal. It would be silly for NW (or and of the three) to offer inducements for you to spend your money elsewhere. With NW/CO, I thik there is hope for a long term merger in the future - when the alliance has become so integral to each airlines customers that they can't bear the thought of the end of the alliance. I don't think that is the attitude NW has toward Delta...

Actually, I can see a good alliance leading to a little route contraction. Why should CO or DL have huge trans-Pac operation when they can route them via NW, IN RETURN FOR NW doing the same to South Amer. via DL or CO, and vice versa. THen the alliance is tigher, more necessary, less likely to break up