Why is my shoulder strap fraying?

I remember how revolutionary it felt when I went through all the custom colors and designs, among other options, when I purchased it online about 15 years ago. I can look past some of the male and female clips breaking, even one breaking that caused the loss of reflective strap that used to hang on the back but I'm really disappointed that over 6-7 of owning the bag, the shoulder strap has been fraying where the handle latch is used to tighten and loosen the bag on my back. I used to just ignore it but it's been getting pretty bad over the last couple of years. It's sewn into the bag and I don't even see it as an option to replace. I'm not sure how this couldn't be a manufacturer defect but how can one prove anything... Any ideas?

EDIT: just figured out how to add an image