Ditto with my grandfather.
He worked most of his life for a very large corporation.
Mandatory retirement age was 65.
After he retired it was all down hill for him.
He even belonged to a country club and enjoyed golf.
But he liked working and being productive.
If I live long enough, I would want “end of first career” to be “beginning of second career.” Until and unless I get so decrepit even that is not possible.
Contracting could also be a good way to dip back into the workforce after a conventional employment career, without expectations of indefinitely long engagement on either side.