I prefer Merino wool shirts to the synthetic tech stuff.. After 2 hours of climbing indoors, none of my tech tees (all around 50 bucks a piece) still smells like I would want to wear it again.
I cannot imagine them lasting more than one day hiking.. sure, you can wash them every day and they'll be dry in the morning..
What about those days, where you cannot do laundry?

The Merino shirt I can wear for 4 days at work before I decide to throw it in the washing machine, just because I don't want to stretch my luck


Lastly, I weigh about 30 pounds less than the average male hiker, so I don't feel very bad about logging about two extra pairs of spare boxers and socks.