They are trying to follow what works for other MMOs, which is phase out old gear and replace it with newer gear. The thing they don't understand is the old gear still remains somewhat relevant for a lot of those other MMOs, and that is because of how long it takes to level up to max level up. Took me a month to get to max level in Star Wars the Old Republic, whereas Destiny took me a few days (not including the grind for all the raid gear, which I didn't bother with until The Dark Below). When I played SWTOR, the older raid gear still helped me out a lot while I was leveling and even in some of the newer raids when I was at max level. This was the case in Destiny year 1. For example, I used Fatebringer for Crota's End and it was still very effective. However, in year 2, all our old gear was useless in pve after the first couple missions.