I would expect increases in the future
 

CO has in recent years has kept their rates tied closely with NW on club rates as they have recriprocal acces to one another. Recently PC members can use WC international locations as well. So I would expect PC lifetime to increase from the present $3720 to $4690 which is what WC is at now. If you are a domestic traveler an even better deal is HP which has access to both clubs in the US for I think about $2500 for lifetime.

The catch is you're only guaranteed lifetime access to the club you buy. The NW/CO club access is for as long as a relationship is in place.

If HP were to sever its relationships, then you're stuck with HP's limited number of clubs.

WC does allow access to more clubs than PC, such as Alitalia, KLM, and a number of other non-NW international clubs.