Why is it that after divorce, women suddenly become children in need of support?

Many of them let their job skills erode or disappear. When/if it comes time for them to go back into the job market, they are at a significant disadvantage. The work world doesn't care that a SAHM shuttled Billy and Suzy to soccer, did laundry, and prepared food. Sure, she could get a job with Merry Maids or Applebee's but it isn't enough to support herself and kid(s).