First of all, the headline is pretty clickbaity -- from the article it seems quite clear that this was a case of competing buyers, and the 8-foot setback is some spurious justification for why one of the buyers didn't move fast enough. Second, many commenters here are arguing that perpetual clauses like this ought to be disallowed. It certainly makes sense to me that clauses like these ought to be converted to regula…
Doesn't your argument that this should be converting to a zoning regulate kind of negate your point that we should want to ensure some level of consistency on a dense city block?
But that if someday in the future there's a greater public need for something that outweights the architectural consistency, there's the flexibility to consider that too, through the existing public mechanisms of zoning changes.
Like if the entire block gets purchased and torn down to put in a single school building, then the setback is no longer needed, because a new kind of consistency can take its place.