Yes agree that all reasons dropped by you will surely improve the steem blockchain, but having a 100%sbd would probably lead to converting of sbd into other crypto coin with the fear of the price dropping down overnight and thus creating less conversion from steem to steempower, due to the absent of steem been generated anymore and users not willing to convert sbd to steem.
Which I believe is responsible for the reward we see today.
On the other hand, if that's what users were doing, the Steem Power will later be sold off as Steem. So might as well get it done with while SBD price is high.
I guess thats the truth