It would be extremely odd for anyone making after-tax investments to say they live paycheck-to-paycheck.

To most people, it means that you have little to no surplus after usual monthly expenses.

That means no elective investment contributions and — more importantly — no contributions to liquid savings.

Failure to maintain liquid savings can turn an unexpected event into a catastrophic tailspin.

EDIT: That said, the other comments here are elucidating. I wonder if there is an unnoticed shift in the language used among young professionals and that this survey is accidentally measuring that instead of real financial change.