>>718562361
Narrative-wise? An asspull, they didn't really do much with the idea anyway (not to mention someone was probably trying to soft-reboot 40k). IRL? Intentionally trying to make Space Marine players gradually rebuy their entire army. Cosmetically? Subjectively uglier helmets and QUALITY designs like the Desolation weapons, the vehicles are all over the place.

They more or less waited until Primaris to make marines in the current scale and improving lackluster rules, doing it with lots of one-off squads in the same fashion as Craftworld Eldar. On the other hand, Citadel did get to making plastic models for 30k, with mixed results on the armor marks.