Great answers here. My wife and I have an old external frame pack that is 30+ years old, and a relatively new pair of internal frame packs. The weight is identical for each pack. And I am not sold on the (put everything in one sack, which makes is harder to dig out later) newer designs.

But our sleeping bags and tent are new, small and light. So small that they don't strap conveniently to the outside of the external frame pack.

Still, I have seen WAY more people carrying too much weight, and too much stuff, because they have a large pack and managed to fill it.

And we don't seem many people who are under-equipped because of a small pack...just happy people with less weight.