I think a case can be made that covenants like this should be disallowed. Sure, allow contracts to be signed, where if a condition is violated then a penalty can be paid. But here? There's no one to buy off to relax the constraint. It's held in perpetuity by the dead hand of the past. To put it another way: there's a property right here (in that setback) that is just sort of floating in the air, not owned by anyone a…
It's also held indirectly by owners of other properties which sale hinged on that restriction applying to all the properties on the street.