Mostly because she did not exist.

There is evidence that Mary Magdalene did write a gospel. But around 325 AD when Constantine convened the Council of Nicea to define Christianity and put together the bible, her gospel was not included in the Christian canon.

(see references to Nag Hammadi – Mary M’s gospel was written in Coptic.)

The real question is – was it not included because the author was female? Or because it was theologically non-standard(i.e. the council of Nicea didn’t think it fit their narrative? I don’t know, and I doubt we will ever know.

Because fictional characters don’t write books.

Back then, women were property & their knowledge did NOT matter!!! The 2 Marys were there to love & support Jesus through his crucifixion. That was their job & they did it well!!! In some ways, I feel the Virgin Mary gave us ALL the Gospels because she birthed Jesus. Had she not given him life, there would not have been any of the Gospels that were written by men. I’ve heard that Mary M had written a Gospel, but man chose to omit it from the printed version of the Bible since it was written by a woman & not considered worthy.

A. She probably was illiterate.

B. The Gospels were written long after Jesus’s death.

C. She was probably too busy raising a child to have time to write anything.

Because it would be pointless. Did you really miss that huge embarrassing episode with the Professor from Harvard ????????

THE Forgery of the Mary Mgdalene Gospel
https://www.cnn.com/2020/09/13/us/jesus-wife-gospel-forgery-sabar/index.html