I agree. I work at a guitar workshop where we go through quite a bit of strings (mostly for guitar, but we get lots of basses too). The quality of strings definitely seems to have taken a dive recently. It's not a HUGE problem, but I've definitely seen more DOA strings than I used to, across nearly every brand.
One manufacturer I have yet to get a poor set from is Thomastik, but they have gotten obscenely expensive. I guess you get what you pay for, they are extremely high quality strings (although the selection of gauges for their bass strings is extremely limited and not always to my taste...). But then again, most players don't use Thomastik strings due to their insane prices, which means I don't have anywhere near the same sample size as with most other brands. If I installed 10 Thomastik sets every week, like I often do with D'Addarios, the chances of getting a bad set would obviously increase. With Thomastiks it's more like 10 sets a year.
Speaking of D'Addario, I have always found them to have superb quality control. I personally don't like D'Addario's clanky/metallic sounding tonal profile (even with their flats!) and I never use them myself, but they have always been the most consistent strings for the money in my experience. Which is why we use them as the "standard" option at the workshop, unless the customer asks for something else (which only around 10-15% of them do, most guitar players don't seem to care much about what type of strings they're playing, as long as they're the right gauge). But during the last 2-3 months I got two sets of Fender bass roundwounds, which I believe are made by D'Addario, where the E-string was completely dead out of the box. I actually think that's the first time I've ever had a problem with brand new D'Addario made strings, and that's quite impressive with the number of sets we go through at the workshop. Hopefully it was just a bad batch, and not a sign of declining QC.
