You exact quote was:

Given that it’s only non-whites that are gone, no skills or technologies were lost ;)

Skills and technology can always be reproduced, more easily if adequate documentation exists. However, that is not your premise. Your premise is no skills or technology would be lost, which is just wrong. All of it will be lost, and whoever will be left will need to go through the long process of learning and reproducing said skills and technology, which can take multiple generations.