This whole business strikes me as very strange! I have been a frequent customer of Norstrom's over the years, and the company is famous (and justly so, in my experience) for its excellent customer service.
Moreover, the claims of six jackets of reputable make disintegrating in the course of six months sounds incredible! Six jackets purchased almost simultaneously would imply a pretty fair rotation, so I can't imagine the wear and tear on any one jacket being that severe. Assuming the jackets were rotated evenly and worn five days a week, that comes out to 30 wearings per jacket. In the past, I have bought some fairly cheap stuff: Macy's-Alfani, Nordstrom house brand, etc. Nothing like what the OP reports has ever happened to me. The notion of a jacket, even one of fairly low quality, disintegrating after no more than 30 wearings sounds literally incredible to me, so contrary is it to my personal experience.