So the ones you own that are losing their elasticity or with threads coming undone, are they not under a warranty?
The warranty on these sort of things is limited I find and, not to brag, but these bib shorts often find their way into my cycling wardrobe, on a complimentary basis from clients ( races/events and some brands that I work with in the business), so even, if there were a warranty of significance I would feel bad applying for it since I did not pay for the bibs in the first place!