I think there is a problem here, that things that happened before the internet became extraorinarily popular in the early 1990s, tend to seem like they never happened. In particular, since we can search for usage after 1995 a lot easier than before, we have a tendency to think that the phrase "mother of all" was never used prior to Saddam Hussein's usage before the first Gulf War.
But I remember that phrase very well - I knew what it meant before Saddam used it, "mother of all cookies" meant "a huge cookie". And I was raised in the U.S. And that's what I thought when
"When the battle becomes a comprehensive one with all types of weapons, the deaths on the allied side will be increased with God's help. When the deaths and the dead mount on them, the infidels will leave and the flag of Alluhu Akbar will fly over the Mother of all Battles." - Saddam Hussein, Baghdad Radio, 20 January 1991
What particularly stuck in my mind, however, was a commentary I read (or heard? or watched?) back in '91 that said the conmmon American usage of that term was NOT, in fact, what Saddam meant. That commentary claimed that Saddam thought the war was literally a mother - that it would give birth to countless other wars later on. And arguably he was correct.
Since the internet prior to Saddam's usage was so small, it's not a good place to look. However, Google Books has a great thing called the Ngram Viewer which shed some light on this. Go to
https://books.google.com/ngrams and type in "mother of all" and you'll find it's not a terribly popular phrase, but its usage increased quite a bit in 1990. The kindred phrase "father of all" was similar in popularity, but did not get a spike in 1990.
