I would be interested to hear what conclusions you draw from this. Please enlighten us!
It varies.
Not everyone MAKES their own strings. A lot of them are contracted out and labeled for this or that customer, more than a few names you'd recognize. Who makes what for who is generally a guarded Gentleman's Aggreement rarely spoken of in public for obvious reasons, if not an out-and-out required anonymity by contract. And of course, the string makers will welcome this additional revenue of these 'private label' arrangements.
This can be a good thing, inasmuch as some of these sellers will shell out for the builders to make them a very consistent product long-term which gains a good reputation. Lots of accessories for the majors are subbed out, you don't really think Fender makes its own polish or picks or cowhide guitar straps, obviously. It's part of a big brand's portfolio, and strings are often included in this.
I'm sure our friend John Moody from GHS strings would tell you that consistency is the biggest target, both in consistently getting the correct alloys from their suppliers and consistency in their manufacturing process. GHS is the most consistent string I can think of, and I've been using them now for 40-odd years, to the point I joke they made 10 million sets of Boomers in the early 70's which they've been selling off since then, they always sound the same. That's VERY hard to do, and amazing at their competitive price points.
In other cases, this or that brand name will let contracts every so often when they need to re-stock on a low-cost-wins basis, and this is often why certain brands seem to be inconsistent, as this constant rotation of makers can result in just that. Try as you might, Good Luck in exactly matching something you had made in Europe last year and something you're making now in VietNam. Different plants, close as you can get on the matching alloy wire, you're simply going to have to allow for a little more 'give' in your QC. You hear this.
This is common in virtually every product. Automobiles are built from an aggregate of 1000's of suppliers, each a specialist in a given part, and this is repeated in many businesses of all types. The days of vertical integration when Ford made everything on their cars save for the Firestone tires (built by their in-laws!) are ancient history.
Whether they suit you or not, this
may very well be why GHS Bassics, a great inexpensive string for example, for a dollar more than the Warwicks may sound and feel as if there's a greater difference in price.
