Yep. Have you ever seen a rower’s shoulders?
Have you seen Usain Bolt’s shoulders? The point remains that most of the power in rowing comes from the legs, and that rowers don’t look so different to triathletes in terms of muscle development. Based on the argument that elite athletes should be good at anything with training, you’d expect them to be able to run a good marathon.
Your suggestion that they’d be quick over longer distances rowing is undoubtedly true, but also completely irrelevant. 2000m rowing is already physiologically an endurance event – it does after all take them longer than Mo’s recent European record took him. There is no such thing as a sprint rower.