I can fully understand the reasons for the cross over between rowing and cycling. There would be more crossover if rowing was a more accessible sport. To get into rowing as a young person, you pretty much have to attend a school that has a rowing program.
Learning to row a single scull requires a certain level of balance and coordination that is similar to learning to ride a bike. Just getting in the boat without flipping it is a challenge for a beginner, and the stroke sequence is something that serious rowers spend years learning to master.
I live adjacent to a tidal creek, and I have a beat up old Maas Aero with fiberglass patches on the bottom. I didn't start to row until I was in my late 20s. I taught myself by reading books. This was before YouTube. I don't claim any great level of proficiency, but I have fun. I should sign up for a training camp. Perhaps they could teach me how to avoid obstacles while rowing facing backwards.