Aw, Chuck. I think youre sort of living in the past. I still have a foot there myself, but its coming out fast.
Of course, I cut my backpacking teeth on external frame packsKelty, JanSport, all the big names. And I still own something of an artifacta Dana Terraframe ($300, more or less, when new). That pack is a truly weird combination of a Dana Designs Astralplane (Danas large, still-hard-to-beat internal-frame pack) with a Dana Gleason-designed external-frame chassis. Really a great pack. Got a 70-pound load? This is the pack for you.
External-frame packs, as a rule, also tend to ventilate a little better. The hard frame does a bit better job of holding the pack frame off your back. Theyre also better at really big loads because they more easily manage the weight transfer from back to hips. And external-frame packs typically have a lot more nooks and crannies for stuffing odds and ends.
All of which mattered, sort of, until about five years ago. Thats when internal-frame packs got so good, and the loads people carried so light, that the advantages of external frame packs began to diminish. As I write this, for instance, I am packed for an overnight climb of Mount Shuksan (9,127 feet), a glaciated, fairly cold peak in North Cascades National Park. Ive been rained off twice, but I am optimistic this time.
Anyway, there was a time when my overnight pack for Shuksantent, sleeping bag, a few pieces of rock/ice protection, clothes, stove, etc.tipped the scales at 45 poundsbefore water, food, and beer (hey, it can be a hot hike!) has been added. Now, my pre-food/water/beer pack is just over 20 pounds. I could go up Rainier with this thing, easily and comfortably. Sleeping bag (MontBell Down Hugger #3; 1 lbs, 7 oz; $279) and tent (Black Diamond Lighthouse; 3 pounds; $430) are in the same small stuff sack.
So do I need an eight-pound, external-frame pack for that? Heck no. My Osprey Aether 60 ($229, under four pounds) is fine. Feels like a big day pack.
So, yeah, external-frames are going extinct. Part of that was due to marketing. Internal-frame makers convinced buyers that external-frame models were uncool, out of date, and primitive. But now the facts speak for themselves. Internal-frame packs are so light and comfortable, with such good packability, and the loads they carry so feathery, that you just dont need a metal-frame behemoth.