No. I'm saying everything else being equal (budget, technology, training etc.) a multi-role air force will always win the war over a specialized air force.
Country A has developed a multi-role aircraft. Country B has developed specialized aircraft for each role fighter, bomber, ground attack and reconnaissance. Country B's specialized aircraft are at least 20% better in their respective roles than Country A's multi-role aircraft. Both countries air forces can afford to operate 100 aircraft. Country A has 100 multi-role jets. Country B has 30 fighters, 30 bombers, 30 ground attack planes and 10 recce planes.
Day one of the war: Country B's 30 fighters face off against Country A's 100 multi-role aircraft in fighter configuration. Country B lose all their fighters. Country A's surviving multi-role planes destroy Country B's remaining air force, now defenseless without their fighter cover.
Day two of the war: Country A's surviving multi-role planes, now unopposed in the air, switch to bomber/ground attack/recce configuration and win the war for Country A.