Everyone seems to get used to the new Primaris Marines. Some are even painting them now with great pleasure. Look at some awesome miniatures from different studios and painters.
New miniatures surely look nice. True-scale has changed their look to better. However, we still hope that old spacemarines won't disappear.
There is some evidence of this in the new book - Dark Imperium.It sais about the events 100 years ahead from this moment. And Primaris Marines there still haven't substitute ordinary ones.
Moreover, the attitude to them is ambiguous. Even Roboute Guilliman calls them "Cawl's blasphemous hordes" and treats only as an instrument.
Cawl himself falls deeper and deeper into Heresy and creates Primaris Marines even from the Traitor Legions and two Lost ones gene-seed.It's really interesting to find out, where it will lead us...
Perhaps, we'll soon see Primaris Marines corrupted by Chaos or completely new - no one knows anything about two Lost Legions...