Once air to air missiles came along, there was little use for cannons, or need to get close to the target. To the point that the US stopped putting guns into their fighters for a while. However, vestigial tails remained on bombers well into the Cold War. Literally tails, just the tail guns. B52s retained them for a while, and on the Soviet side, they were kept all the way through to the Tu 22M Backfire, albeit radar directed, not manually gunned. By the time one got to the modern bombers, B1/ Tu160 flew so low and fast that it was considered so hard to shoot down that there was little benefit to the tail gun. (An unarmed EF111 was credited with a fighter kill by causing the chasing aircraft to crash). And the B2, of course, is supposed to not be seen in the first place.

There is one notable rebirth. It was not unheard of for large multi engined aircraft to carry missiles of their own. In 1982, for example, Nimrod maritime patrol aircraft were fitted with Sidewinder missiles,, but these were offensively intended, to shoot down any Argentine maritime patrol or reconnaissance aircraft they might happen to bump into, making them the largest fighters in the world