Yes, I agree. Not making the content visible to all, would automatically decline rewards. UIs would hide encrypted content.

I think, at some point in the future reward pool for content will be removed anyway, once SMTs show different use cases for rewarding content. Tribes already showing that Steem can function fine without the Steem reward pool.

Regarding removing the content after some time, it is a reasonable feature to give the users, maybe after a year or two. There can also be a return of rewards back to the pool when removing content or revoking authorization to display the content.