I must of misunderstood your post. I assumed you meant that they recycled all the memory chips from old GDDR5 GPUs and ended up using those in some newer GPUs as rebranded chinese ones. What you are saying makes perfect sense.

Basically if only 1 memory chip is faulty and you can still sell the GPU for >$100 then its worth the labor to just replace that 1 memory chip. Probably will take less than an hour from start to finish. I had an old old Bitcoin SHA256 ASIC called the Jupiter (or Saturn) ASIC. This was back in 2014-2015 and I had many of the VRMs die on some units and I basically removed the dead ones and took working ones from other boards. Since I was only replacing 1 VRM instead of all of them it was worth while.