One thing, more breathable fabrics are just not as structurally sound. They're also not natural fabrics. The individual threads of synthetic fabrics are much smaller.

Another, automatic dryers means clothes aren't being hung out to air dry, which means a whole lot less ironing. Mentioned that before, but the result of that is that clothes aren't being starched. One of the things starch does, other than removing wrinkles is to provide some structure to clothing. Further, stains stick to the starch rather than the clothing fibers which makes them easier to clean which then leads to less wear and tear during cleaning. Longer life span for clothing.

I'm sure there's a whole lot more reasons, but off the top of my head, that's what I've got.