@blocktrades is certainly the subject matter expert on this, and I believe he's published a number of posts explaining the careful design of the system. The discussion was had amongst the Witnesses who are the ultimate arbiters of these decisions. Those are the people stakeholders voted for.

What the SPS is supposed to do is fund projects that create sufficient value to justify the expenditure, and that's the analysis people should perform when determining whether to vote on a proposal. If there are no good proposals, then people shouldn't vote on any proposals, and that money will go unspent. That's how you roll back the SPS, if it doesn't generate any value, don't use it or downvote proposals you don't like.