I do not really understand your concern. What you say "duplication" is not harmful in any way, but a path towards progress. A new programming language is like

I do not really understand your concern. What you say "duplication" is not harmful in any way, but a path towards progress. A new programming language is like a new material. You can build chairs and tables in wood. But when a new metal is introduced, is it worth to "duplicate" the work and build chairs in the new material? Maybe, who knows. You may end up with a chair that has surprising new properties, impossible to have in wood. Or maybe it is worse in any measurable way, but some people may still prefer it for some reason. Would you complain to the discoverer of a new material that they should not build chairs in that material, because chairs are already solved (by using wood), and they are just losing time by reinventing the wheel? Technology advances by the continued reinvention of the wheel. Rewriting old algorithms in new languages is a beautiful part of that.