That would be "60 year olds who have been office workers most of their working life"

60-year-olds who worked blue-collar for a significant part of their life, this is not so obviously true for.

Also probably not true for 60-year-olds who worked in other non-office jobs, like acting or sports.

There have been a variety of well-paid jobs that didn't use computers that a 60-year-old might have done over their life, meaning that this can't even be broken up along class/income lines.