i'm still just looking for one example where anyone in film or music was famous at one time and then out of desperation had to take a common job where common people could point and stare at them .
Another change from your original question. This one's easy - several websites
answer this question:
Jackie Earl Haley delivered pizza before getting back into acting.
Sly Stone worked in a coffee shop in LA
Margo Kidder works in a diner in Montana
Natasha Lyonne worked at a Denny's in Hollywood before crashing hard and
then getting back into acting.
When I was living near Hollywood/La Brea I saw Danny Bonaduce living in his
car in the area. Tourists would ask for his autograph.
Willie Aames worked a series of odd jobs including a janitor in an office building
Taran Noah Smith blew all his money and ended up delivering pizzas and working
in fast food places.
Jodie Sweetin married a cop and then fell into drug addiction. Don't know if she
ever had a common job where common people could point and stare at her.
It is widely rumored here in LA that Leif Garrett works as an "escort" (both men
and women) capitalizing on his teen idol past. Don't know if that's true.
Now you have several examples. Even actors have to make a living so when
they can't find acting work they take regular jobs.