I'm sorry but this is just mind-blowing to me (the Steely Dan is not rock part, the yacht rock part is what it is, I can't say that's unreasonable).
Artful, jazzy rock is still rock. Is Yes not a rock band? Is Phish not a rock band? I can accept that some of Steely Dan's catalog is so fusion-influenced pop that it really isn't rock, but they've made equally as much genuine rock. Fagen and Becker draw their influences from old-school R&B as much as they do from Coltrane and Miles Davis.
With all friendly respect, the notion that "most musicians would not classify Steely Dan as a rock band" is nonsense.