Yes, the original post concedes there's probably no such thing as a perfect system. But what we can do it make it less profitable to engage in behavior we don't want (eg self voting, vote selling) and more profitable to engage in behavior we do want (eg honest curation.
The right incentives are probably more powerful and effective than you have you mind. If curation pays a lot more and a moderate amount of free downvotes are available, the threat to any obvious abuse is very real. If we get the numbers right, it should be sufficient to deter most misbehavior to the point where we have enough free downvotes to take care of the actual misbehavior that were not deterred.
Also, while I personally believe a functional base economy is more important and essential for SMTs to really take off, I don't really think SMTs vs Economic Improvement is a dichotomy. Realistically, even if it took priority, it doesn't require a lot of work from a coding standpoint. It's only a small exaggeration to say that @vandeberg could knock it out in an afternoon (well maybe like a week :p). Think about how easy these changes are to implement and how important they are compared to the complexity and uncertainty of an undertaking like SMTs built on a broken economy system. If we're half right about these economic changes, then it'll represent the greatest value for cost and time investment than any other undertaking.