So far I have not discovered a way to refit exisitng gas mining and mineral mining stations with the latest technology. Has anybody discovered how to do this? It does not seem that they upgrade by themselves and we are thus losing out on potential. This also seems to be true for research stations.
I still believe that construction ships should be capable of in-place refits on existing constructions. If they are capable of building one from raw materials, they can certainly take one apart to make a few modifications.
I don't think it matters HOW the thing is replaced. People would be perfectly happy to simply scrap and rebuild, but neither option exists independently of the editor.