It is still likely a derived work. Looks more to me in the example it was just practised the right to make changes to the original work which one could do under the given circumstances which is normally a reciprocal license - floss or else - which means even when if 100% of all letters in all files have been changed, one could still not do more than the original license granted.

and that is normally _not_ what you wrote:

> the copyright holder [sic!] of the new program could license it however s/he wanted.

However if sole copyright holder - real, not imagined - she sure can license it - or not. Or different another day.