will this fall on deaf ears?
To be clear I am not advocating turning off rewards (though it wouldn't bother me really as I think they are mostly worthless in their present form) and I doubt there is much support for it right now. I would prefer to improve the curation system so it can channel rewards to more value adding activities.
At some point if we conclude that we can't make it work then it would be better to pivot. One way to do that may be to have STEEM decline from competing with SMTs in the reward-voting game and let SMTs experiment with their own solutions. STEEM can instead focus on being a native coin (including as reserve and bridge asset for SMTs) and access and governance token for the network with much lower inflation.
I don't agree with your view on SBD, I view it as a complementary asset. Regarding SMTs, I don't think it is possible to prevent external trading. No one needs permission to do it.