Because it wasn't her body? It wasn't her face or life to live? Why would she NOT want to go back to her old body? If anything MiM shows that she did want to just not by anyone else. She knows tons of magical and otherworldy type of forces who could have assisted in doing whatever needed to be done. She could've teamed with Wolverine to try and find the machines The Hand used. She could've attacked Mojo and Spiral to force them to reverse it. The journey to see if it could've been done is a whole personal story arc for her in itself. The type of deep insight into her mindset that fans have been clamoring for.
Both can be victims and Betsy can still be in the wrong for how she handled things later.