Why use fighters when armed corvettes can fight effectively?

Why rely on one-person starfighters when small corvettes such as the Millennium Falcon can fight fighters, capital ships, and stations?

Fighters still provide mobile offensive and defensive screens around the fleet; the roles are complementary rather than interchangeable.

Fighters form part of both the defensive screen around a force and the offensive screen moving ahead of it. A capable corvette does not eliminate the need for fast, numerous aircraft that can intercept, scout, and mass from a carrier. Fighters also cannot replace the capital ship's own close-in weapons or dedicated escorts. Each layer protects the fleet in a different way, so no single small craft can perform every task.