Why surrender a Kingdom in your family for generations to another House (granted they are friendly for now....). I wouldn't characterise her childbearing record as atrocious, sounds like she's being blamed for her kids dying.
I'm not blaming her, I just think that (much like her mother and sister-in-law, the dauphine), she barely had time to recover between the pregnancies:
Mom, married in December 1666
Ferdinand Wenzel (b.September 1667) - I'm guessing he was a wedding night baby.
Maria Antonia (b. January 1669)
Johann Leopold (b. February 1670)
Maria Anna (b.February 1672)
Plus she had 2 miscarriages - in 1668 and 1671 and when she died according to the one German source on her, she was several months pregnant as well.
Marie Anne Victoire of Bavaria, Dauphine de France married in March 1680
Miscarriage (1680)
Miscarriage (1681)
Louis, Duc de Bourgogne (b.August 1682)
Philippe, Duc d'Anjou (b.December 1683)
3 Miscarriages in 1685!
Charles, Duc de Berri (b. 1686)
Maria Antonia of Austria, married in 1685
Miscarriage (1687)
Miscarriage (1688)
Leopold Ferdinand (b.April 1689)
Anton (b.1690)
Miscarriage (1691)
Josef Ferdinand Leopold (b.October 1692)
Is it any wonder that these women died? Its as Marie Leszczynska said, always either being taken to bed or brought to bed.