Was it hard to give us OG Fallen with the cool armor from Destiny 1 with some interesting House of Rain colors instead of just saying that the House of Dusk stole the colors from House of Rain but still look like Destiny 2 desperate Fallen with their Armors?
The development time for any project is determined by the things they can get done and the things they cannot.
It is fine as an example or it might be a step into us seeing one thing, drawing a conclusion, and finding out otherwise. It's a good stabilization point too. Too much change brings about when changes occur, why was the lore updated this way, and others.