Sure, within a small host or ISP, that may be doable; even then, I'd consider it a stretch. But if we were to limit it to those constraints, when will this ever

Sure, within a small host or ISP, that may be doable; even then, I'd consider it a stretch. But if we were to limit it to those constraints, when will this ever be exploited except as a PoC? No entity large enough to actually want to run this exploit on has an architecture where this would be feasible (due to things like geodistribution and load balancing), nor would be hosted on a provider so small that their IP pool can be exploited in the manner described. If I were an attacker, I'd focus on something with much bigger RoI.