I really like your thought process, explanations and vision for Steem. However, I disagree with your conclusions.
I don't think SPS is necessary especially if it takes away from author/curation reward pool. If SPS is funded with removal of interests on SP that would make more sense to me. I do think EIP is a positive change.
My reason is making Steem an attractive asset to invest. Simple economics suggest more people buy and power up than sell prices go up. I think EIP will make Steem more attractive. Primarily, because most social media users are content consumer and not content creators. Giving content consumers a fair chance to be rewarded by investing will create a better economics. I think institutional investors would follow the suit, if retail is happy to invest.
Even yourself mention in one of the comments the importance of the token price. That will be the biggest marketing needed.
Bottomline, if average users are not interested to invest their hard earned money into Steem why should large investors bother? For these reasons EIP makes sense to me, and SPS seems to undermine that. I like EIP, but with combination of SPS that potential could take away from authors/curators probably brings us back to where we are right now.