Yes, but many people have been designsted as "having stopped looking for work", which means the statistic doesn't count them.
Additionally, those who are employed perhaps are underemployed, working as an Uber driver or bartender or chipotle or etc.
>the economy has improved
For the top 6% of Americans that are millionaires, it absolutely has improved. Most of their income is from capital gains, dividends, and business equity.
The average person with student loans has almost none of these things. They are relying on a wage from a job that requires them usually to pay rent, own a car, buy a monthly transport card, and so on.
When you are only making $1400-2000 per month after tax, and $1,000 of that is out the door on work-related expenses alone (rent, transport, insurance, phone), there isn't much left over for a $300 per month student loan payment.
Disclaimer: Don't shoot the messenger. These are merely my thoughts on what is happening. Please reply with criticism.