An airship drone mothership becomes another asset the fleet must defend

Could rigid airships return as drone motherships for long-endurance operations?

Potentially, but their size and vulnerability create a major defensive requirement that cannot be assumed away.

A rigid airship could theoretically remain on station and support drones for long periods. Its main weakness is that it becomes a conspicuous target. Claims that it can remain safely beyond enemy reach do not remove the need to defend it. Any assessment must count the escort and protection costs of the enabling platform.