Very true... Either she is not dependable, not very reliable, not on time. etc., or something else that makes her not a good employee. Otherwise, she would have moved up into management after a few years of hard work (or at least much higher wages).
So, don’t blame others or your situation, blame yourself!
Then work to improve...
She has been in the workforce for 16 years and named close to 10 different job changes. I don’t think she has every been employed in one job for longer than a year. Yet, she need a top salary to start?