It's more of a "functional obsolescence" than anything else. Ocean-going carriers responded to the growing Asia-U.S. container trade by building larger ships to gain competitive pricing advantages through economies of scale, but many shippers have begun complaining that this has resulted in a scaling back in the number of ships making port calls for them.
The airline industry offers an interesting parallel. As passenger loads increase between two points, the airline industry does not respond by operating these routes with larger aircraft, but by offering more frequent service with the same type of aircraft.
In essence, the shippers are willing to pay slightly more with a carrier that uses two 3500-TEU ships per week than with a carrier than runs a single 7000-TEU ship per week.
Shippers aren't willing to pay more for diddly.....
i agree they like frequency and port coverage but they could care not a whit if the ship was 3500 teu or 35,000 teu so long as the price was right and the goods got to their buyer within the time specified.