I personally absolutely don't understand why old ornaments are not available for purchase. And I don't agree with that decision. It's not about being greedy (I wouldn't be concern about it, everyone thinks that anyway), it's about giving players choice so there is literally no reason not to do it.
[u][b]Weapons:[/b][/u]
I'm talking about LEGENDARY WEAPON ORNAMENTS
If you're not new (or you just look into collections/weapons/ornaments) you know that there are quite a lot of old [b]unobtainable[/b] ornaments... even for few weapons that are not sunset... and when you look at them, you find that except several "newest" ones, they were not tied to some activity or achievement but they were from Eververse...
So my point is, why don't you, Bungie, put all of those "Eververse only" ornaments into their own category into Eververse where you'd have those, that you don't own yet but only for weapons you have unlocked in the past... There are still players who use those weapons.
[u][b]Armor:[/b][/u]
This one is definitely arguable but still...
after you, Bungie, introduced Armor Synthesis, you still keep all older legendary weapon ornaments only for Silver. I know it's a clever marketing move but imagine how much money it's for new players (not me)... it's not rewarding at all to get them (compared to grinding BD). Why not, again, make a separate category in Eververse where you could buy all older "Eververse only" seasonal armor ornaments for BD. Give us the option to choose in-game time vs. money. Doesn't matter if one piece would cost e.g. 2,5k BD... it would be at least some dilemma whether to grind BD or simply pay some money.
Another thing... when the season ends, the armor can have e.g. two seasons delay, and only after those two seasons, you would be able to buy it for BD again (without weekly rotation)... but it would be twice as expensive compared to the original season it was introduced in.