At one time low altitude was the best way to evade air defense as fighters didn't have look down/shoot down radar capability. They do now, so the low altitude

At one time low altitude was the best way to evade air defense as fighters didn't have look down/shoot down radar capability. They do now, so the low altitude mission might help with ground based radar (by using the earth and geographic features to hide), but an enemy with modern fighters and AWACS capability makes this profile difficult.