These days if you have the money, you can go very light. You can now backpack comfortably for a week with 10 Kg. On my wilderness survival challenge this summer we are taking about 5 kg for 5 days and I think we will live well (less the sleeping bags we do not have). Going Ultralight just costs money. Good gear that last may be heavier but cost less. Selection for the situation is far more important than weight.