A lot of boils down to overall QC and attention to details, not to mention which textiles can be used or not by said company or companies.
Take a look at the tape on the seam sealing on a Sitka jacket (or Arc'Teryx for that matter) compared to FL and other hunting or non-hunting brands; seam/tape sealing is required for anything to stay dry for long and I have witnessed less than perfect taping on FL jackets. Also, you have substantial financial capabilities and years of experience in textiles with WL Gore, etc. I don't think FL is a bad brand at all, but the same comparison can be made with other companies, gear, etc. The devil is really in the details many times, as is the overall quality and features of certain textiles; take cheap big-box fleece, for example. Most of the time, that stuff will pill and fuzz out really quickly. I have fleece pieces from Sitka, Arc'Teryx, Patagonia, etc. and some I have have had for years.
Gore-Tex, Windstopper, etc. definitely have the lion's share of the market, but they are quality textiles that perform in a lot of varied conditions.