Codeshare Partners vs. Skyteam Members
As I was thinking about the impending codeshare relationship between GOL and DL, the thought occurred to me that a codeshare partner can be more valuable than a ST partner. I will hopefully be able to buy a DL ticket that connects to a GOL operated flight with a through fare. The codeshare flights will earn status miles.
Contrast that with a ST member like UX that so far does not seem to have any codeshares with DL. I may connect to a UX flight in MAD or BCN, but it would seem that the UX flight would be a separate ticket.
Now ultimately, I hope GOL joins ST, but as long as I can fly to their destinations on a single ticket/fare and earn MQMs, I don't see that ST membership is that crucial.
Another example... I have been using AS flights for years, earning DL MQMs and miles even though they are not ST members.