You clearly don't know what the term upward mobility means. It doesn't necessarily mean moving from one class to another - though that WOULD be included within its scope, however extraordinary an example it may be.
It can mean moving within a class.
Surely most people want to better their station. To argue against that is insane and counter to every observable fact about human nature.
>It can mean moving within a class.
It can, but it's not how it's used most of the time, so kind of a pedantic distinction.
And many do not even want to "move within a class" that much. They'd be satisfied to keep their job and retain the same constant purchasing power and ability to buy food, feed family, pay rent/morgage, year after year.