I don't think that's the case! If it is relevant content, the etiquette seems to be simply to state that it is cross-posted, and to provide a link to the original.
On your above point about why people are moving, well, for me (and I'm not moving entirely), there is (1) the niche aspect (2) the starting over but with the experience of Steem (3) the more grounded, organic approach to interacting and curating manually, without the layers of automation and gaming which have developed over here - it's refreshing (4) earning, sure, but that has always been a by-product for me, a consequence of self-expression, not the driver of it.
I'm getting more into it with my personal account. It is pretty exciting right now how much content is over there, albeit a little sad that there's less here. ha. At the end of the day, I think there are strong futures ahead for both platforms hopefully.
Yes agree, that's it - the one doesn't take away from the other and both can grow simultaneously...
Thanks for the perspective! :)