SPS is not controlled by a few. Every single Steem stakeholder gets to vote on proposals, just as they currently get to vote on content. Sure the stake distribution isn't all that flat to say the least but this applies equally to the existing reward voting. To the extent that it has any validity at all, your comment is more about Steem in general than about anything specific to SPS.
RE: Normie Talk - HF21 Explained (SPS + EIP) What it is and what happens next