The problem with civilian style clothing is that functionality is not at the core of its design. How it looks and the way you can market them is, a lot of times, the deciding factor. What you need to do my fine feathered friend is invest in some pants that will go the distance. A person should only have about 10 to 14 pairs of pants at all. A pair or three of dress / work pants depending if you work in an office environment or not. A couple of pair of jeans so when you go out you can look casual and blend in. The rest, of course, should be tactical clothing!
Lets first examine the pants of the BDU. BDU stands for “Battle Dress Uniform”, and they were the standard pants of the US military up until 2005. These pants are ones to behold. I prefer Propper brand BDU pants myself, though I have never had any of the TRU-SPEC stuff to compare it with. These pants are built with “function over form” as its mantra. First you get to pick what kind of material the pants are made of. “Battle Rip” which is a 65/35 Poly/Cotton Ripstop (Ripstop means there are little squares woven into the fabric that will catch and isolate a rip so it doesn't spread through the whole of the fabric) is a good all season pant. My preference for material is a 60% cotton / 40% polyester twill. This is a heavier weight material which is good if you live further up north. Moving on, the BDU has some other features like six pockets, a thick button fly, and waist tabs that work to cinch the waistline if the pants are too wide. BDU pants come in various colors like black, tan, tiger stripe, and woodland camo. The best thing about BDU pants are they are constructed with reenforced knees and a reenforced seat. This will help your wear and tear problem.
Even if you don't like the style you could just get one pair for heavier activity where you would more easily wear out your other pants. Put one pair into rotation and that is one day less of wearing out another pair of your more favorite pants.
Anyhow I'll stop going on about pants now. I hope you manage to find a solution to your problem.