Bearishgirl,
one counter point to your argument is that almost everyone is employable at the right wage. maybe those 55-65 y/o don’t want to accept a wage appropriate to their skill level?
If I can hire a 30 y/o with similar skill level for 30% less salary and benefits, I, as a employer with a bottom line, would be foolish to hire someone who ask for much higher salary, whatever their age may be.