Why do smartphones barely outlive their warranty period? Check the statistics on how long most people keep their phone before voluntarily replacing it, and it makes a lot more sense. Why invest in the premium components and workmanship to make your phone last 5 years, if 95% of your customers will not use it for more than 18 months? (These numbers are made up, but from what I remember, the reality is not far off from that).
I could totally believe a similar thing being at play for backpacks, jackets, shoes, etc. where the people who keep their stuff long enough to even notice it falling apart are a maybe vocal, but small minority.