I'm retired now myself but when I was working I never had a problem with the age factor as I worked nearly all my adult life on a commission basis and had much experience that I was in demand up and until I actually decided to retire. My last employer when I was working actually tried to talk me out of retiring.
Perhaps it does just come down to money. In my case I made my employer money. I decided to make myself invaluable I suppose at an early age in my adult life and it paid off.
Commissioned sales: The lowest paying easy job and the highest paying hard job. :)