And how can you say that once a mitzva is discontinued it is a deviation to reinstitute it? That might hold true if the mitzva was specifically discontinued (e.g. the chachamim were gozer not to blow shofar on shabbos so we cannot reinstitute it). But that is not the case by Techeiles. There was never a gezeira to not wear Techeiles. What happened was that people were unable to wear it hence they didn’t wear it. Let’s say the government would prohibit importing esrogim and no one was able to get an esrog. Would you say that we can no longer fulfill the mitzva of esrog because it’s not part of the Mesorah?
You are arbitrarily making up this distinction between intended discontinuation and passive discontinuation. Who said that is even a relevant criterion?? Again, what the geder for when the muchzak switches from having the mitzvah to not having it, go ask someone who has a legitimate opinion — it’s definitely not simple at all.