You're absolutely right. I don't know if they went with a united front on this expedition, but in general all the urban centres and regions of the Maritimes (and to some extent the Atlantic Provinces but it seems more prevalent in the Maritimes) are in an artificial competition with each other. Once one area gets something, everyone else wants it too. The one thing I find different about the ports talk is that they're all saying their container terminal will "work together" with the others in the region within the Atlantic Gateway. Whether that actually gets to be the case or whether we get screwed with the same old competition remains to be seen.
In my opinion, the thing holding the region back isn't the lack of one clear major urban centre as some believe (after all, even though the population difference isn't as severe as in other regions, it's pretty clear who the major centre in the Maritimes is), but it's the competition between centres. There's no reason why we need to prop up an already major centre, but there's also no reason why all our major centres should be in competition with each other. If all the major centres in the maritimes were allowed the opportunity to build on their strengths without political interference (including artificial centralization and artificial decentralization), we'd be in much better shape. Unfortunately, politics tends to lead economics in this part of the world.
Aside: this might be better suited to another thread, but I can't think of which one it would be best suited to nor can I think of how to create a new one without being too close to a duplicate of an existing thread.