You're overestimating value of low-tier legendaries and afraid them to lose value, because you hoard them a lot. But value loss is imminent in old and dying mod like NI, people are leaving, items supply increase, but demand only less and less, because old players already have better gear and less new players (who might want that low-tier gear) then before.
From another side, top-level legendaries better keep their value, demand is higher and market is smaller too.
From another side, top-level legendaries better keep their value, demand is higher and market is smaller too.