Missile submunitions and the target's freedom to manoeuvre

Do missile manufacturers consider submunitions, and when would they make sense?

Yes, especially for some low-flying targets. A single larger warhead is preferred here for covering the volume around a freely manoeuvring aircraft.

Missile manufacturers continue to consider submunitions. Their value depends on the target and role. Helicopters and other low-flying aircraft are examples where the approach can make sense. A freely manoeuvring aircraft requires effects across a larger surrounding volume. One larger warhead is preferred for that case because of the square-cube relationship invoked here.