With all these buy-it-for-life garments, there needs to be some kind of control to demonstrate the advantage of the BIFL version. Some heavy, $100 wool hoody might last 10+ years, but so has my $20 cotton one from Americal Apparel (and I don't need the additional warmth from wool, I'd wear my Pata Nano-Air if I did). A $300 GoRuck pack is bomber, but my $50 North Face backpack from college has lasted 12 years through snowy winters, international traveling, hiking etc. Sometimes "overbuilt" is just that and not really needed, unless you really treat your belongings roughly (you're an actual soldier or thru-hiker).
I definitely don't think there is any reliable connection between price and durability. North Face or Jansport backpacks are classic examples of items that are well-known for their durability but are not very expensive up front.
Patagonia is not an inexpensive clothing brand, but it's also far from the most expensive clothing brand.