Although a pain point kind of seems obvious, Peloton is successful because cycling by itself is "approachable". Anyone can hop on a bike and just start cycling, doesn't matter on your gender, weight, or conditioning.
While rowing, eh.. You said it yourself, people avoid it in gyms like the plague. Don't get me wrong, I love rowing for the same reasons you do, rowing is the activity I do the most during the week.
It's just that a lot of people do not like rowing, or/and are scared of it, and the biggest "problem", it is hard, way harder than anything else in the gym.
So it seems that you are naturally blocked with a certain ceiling as to how much you can grow and where. While you are establishing a moat yourself to keep competitors away, the bigger question is how is the customer going to cross the "rowing moat" to even try your product?