I haven’t read this whole thread so forgive me if this has already been mentioned..
The pocket bags on all my IH jeans are the weakest link and almost all of them have had to be repaired. They could be much thicker or even made with a light canvas and still be comfortable.
I don't know if something has changed or what, but my last two pair (666 14oz OD, 666 vintage 18oz) have had front pocket issues at the upper interior pocket hole seams. The pocket fabric on the 14oz, and the tape AND pocket fabric on the 18oz, have worn through very early in the journey. I have many lesser jeans that have never exhibited these behaviors, so I am pretty surprised by it.
Finally, the seams devolved similarly, but later in the lifespan of my old 634-SII, and then the pockets developed holes. I never thought anything of it because these jeans were getting patched by the time this happened, but I am a little disappointed to see this happening on these other, younger jeans.
I agree that this is a weak link in otherwise rock-solid jeans and appears to be common across all the denim IH that I have worn long enough.
I don't see this in any other IH pants, but then again, I wear jeans more frequently than I do those so hard to say whether this is jeans-specific.