She quit because she didn't want to work any more. Her youngest is in high school so if she wanted to stay home while they were young she could have, and then begun working part time 8 years ago if she wanted. She didn't want to. I suspect things will work out just fine for her anyway.
Nice timing.....Of course, this sort of thing doesn't happen every day to every family, and I'm sure Silda will be financially stable.....but what if she was just a regular middle class Jane who'd given up her thriving career in order to support her husband's dream? What if middle-class Jane's husband did something that caused him to be fired? What would Jane do then? How much dream does a 45-year-old lady who may or may not have a college degree and has been out of the work force for 10, 15, or 20 years have left?