I'd say they haven't found a career path or job that they enjoy.
A lot of people graduate from college with no desire to work or build a career. They expect employers to simply plunk down wads of cash because they graduated from a university and then they'll kick back and receive steady raises and a corner office.
Most likely any job they have is just something to pay the bills with. They're not looking to climb the ladder within the organization.
Odds are they want to come to work, do what is required, be left alone, and go home with a paycheck on the 1st and 15th.
They'd be content if things never changed until they retired.
It's a "Living for the weekend" mindset.
When one really doesn't care for their job they're not likely to invest a lot of their own time becoming an expert in the field. They're not going do anymore than is required. They're not going to show enthusiasm on the job nor volunteer to take on more assignments.
They can't wait for Friday 5 O'clock to arrive!
When you don't care it shows in your work efforts and your attitude.
Both bosses and co-workers can spot dead weight or slackers.
No effort was made to be #1 on the team or in the company.
Most people (mentally quit) their jobs before they get fired!
They never viewed their job as a "career" but instead it was something they kind of "fell into" and the pay was decent.
Once they get fired they look for another "job" not a career and the whole cycle repeats itself until they finally retire or are forced to.