Really nothing more to add except that it seems AMD builds their platforms for sustainability making them age pretty well. This is something I personally like really well rather than a „throw away“ mentality.
Gotta admit I agree, the fact an r9 390 is still relevant for 1080p but based on a 7 year old gpu says alot about amd, though it would be nice if this performance existed out the gate. I remember looking at r9 290 reviews and it lost to the GTX 780, now it smokes it and competes with a GTX 970/1060 3gb or rx570 4gb