Yes, the original phrase is meant to announce a death and immediately proclaim a successor. The two elements are juxtaposed to emphasize the continuity of a lineage, leaving no room for doubt about transfer of power. In a single breath, one reign ends and another begins.
For example when Queen Elizabeth died, some people commented “The Queen is dead, long live the Queen” when it would have been more appropriate to say “The Queen is dead, long live the King.”
Jezebel is dead, and it has no successor. That certainly calls for a commemoration of its impact in a fond eulogy. But sadly we cannot yet celebrate a new Jezebel.