if they form a society conductive to long-term pursuit of the project

Why would they want to? A modern dolphin can get basically all the food its needs with minimal effort,so the main competition is intra-species. So for a dolphin society to advance technologically you would require every individual within it to give up their own reprodutive fitness but putting time and energy into the great project with no immediate benefit. For a technological society to develop it isnt enough that with sufficient coordination they could do so, but that it is in their self interest at every step along the way.

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It may also be possible to fall into local maxima and not get out of them even once a species has got a starting level of technology. Consider that humans spent 2.6 million years or so at paleolithic technology levels, and were probably only knocked out of it y sudden environmental change not by a gradual process of improving technology.