A guy I know worked for an IRS regional office in an enforcement/audit role for something like 40 years. He had something like 75 co-workers in that role in 1999 and retired with 8. Technology actually increased their workload, but with less people, they only targeted the most egregious violations.
He stuck around because he was really passionate & dedicated to his work. He was a guru on some very specific/arcane areas and wanted to transition it to somebody. That never panned out, so he gave up and left when his health declined.