devastated

Aftershocks still shook the earth when pilot Gato Urrutia crash landed on a makeshift runway February, 1976. After a 7.5 magnitude quake devastated much of the region, many local roads were used as runways to transfer emergency goods and supplies to survivors.

If B-17's and B-24's needed altitude to mitigate flak and interceptors, then why weren't the medium bombers devastated?