I think since air power began the emphasis was on bombing and recce; however, when these roles became a threat, air-to-air fighting became fundamentally necessary in order to defend the ground troops. Lose control of the airspace and carnage results.
We are lucky that recent conflicts have been more or less all-offensive but, unless one can guarantee the future enemy will not have an air force, it is a good idea to maintain a strong fighter force, even if it is part of a multi-role capability.