My everyday and short hike socks are basically a 70% wool knock off of the British issue sock - loopstich sole heel and toes of the foot, ribbed elsewhere and very comfortable. Very long lasting.
For canoeing and major hikes I use Smartwool - usually their Trekking socks - and I find them supurb. Tough, long lasting, quick to regain bounce after use (and a wash) and very very comfortable - my only reason for not using Smartwool all the time is the price!
I have used Smartwool in the jungle, in the desert, in temperate zones, up mountains and in rivers and never had a problem.
Boots I wear out fairly quickly but I can honestly say that I have some Smartwool socks that have outlasted some boots and canoe shoes!
I think that the original Smartwool socks may be tougher than the current offerings and that washing them carefully prolongs their life (mine get coolwashed on wool cycle at home or handwashed with bio soap in the field) and an individuals feet and walking action may have some contribution to make on how long socks last.
Another thing is I use up a great deal of shock absorbing insoles - it could be that they take some of the wear instead of the socks.......maybe.