High-speed strike weapons (hypersonic missiles) are the future of modern warfare, not drones. They will render our aircraft carriers obsolete.
We’ve had high speed strike weapons for generations. They’re called ICBMs. High speed strike weapons are vulnerable to having their launch points hit in a surprise first strike.
The point of bombers has been that you can get them in the air at the first sign of trouble, and then call them back if it turns out to not be an attack.
Bombers can carry high speed strike weapons, and unmanned bombers can stay aloft for a long time.