What is good argument according to Powell that all 4 Gospels were written prior to 70 AD?

According to scholar Michael Powell, a strong argument for the early dating of all four Gospels before 70 AD is the absence of references to the destruction of the Jerusalem Temple, which occurred in that year. The Gospels contain significant events and teachings of Jesus that would likely have been interpreted in light of the Temple's destruction if they had been written afterwards. Additionally, Powell points to the rapid spread of Christianity and the need for authoritative texts to guide early believers as further evidence supporting an earlier composition date. This context suggests that the Gospels were written while eyewitnesses were still alive and the events were fresh in memory.