What is wrong with conventional fluid?
If 99% (or more) vehicles serve out their lives with conventional fluid, then conventional is fine. It works. Synthetic fluid has zero advantage in those applications.
Why should a manufacturer use a more expensive formulation when it's not needed and the average consumer (not BITOG member) doesn't care?
IF a manufacturer uses a synthetic, perhaps they have a reason to. Perhaps, in that application (performance, heat, towing, whatever) they have determined that it is worth the extra cost.
But not every car, not every vehicle, needs a synthetic fluid. Legit. Serious. Regular fluid works great.
Personal examples from cars I've owned*.
1. 1977 Oldsmobile, 200,000 miles on the original transmission, using DEXRON conventional, fluid. Nothing else was made back then. It was my first car and saw a lot of very hard driving. I was a kid.
2. 1990 Toyota 4 Runner. Lots of 4 Wheeling and rough use. Still on the road, 300,000 miles on conventional (DEX I, then II, then III, then Toyota Type-IV).
3. 2002 Volvo T5 Wagon, still being driven by my daughter, 200,000 miles on JWS-3309 fluid.
4. 2002 Volvo XC, still on the road, 265,000 miles using, wait for it, wait for it, conventional JWS-3309 fluid.
If I can get over 200,000 miles from a transmission that used nothing but conventional fluid, why do you want to spend more on synthetic?
Here is your logic applied to a different aspect of automotive manufacture: Why doesn't every car come with Z rated tires? Why are some companies using only H rated tires? Is it just for cost savings?
Same legit answer; not every consumer, not every vehicle, needs the performance that Z rated tires offer. Most are just fine with H rated tires. They'll never see the speed/heat that demands a Z rating.
If the base stock of a fluid matters to you, then feel free to change it out yourself. That's what I did on my Tundra at 25,000 miles. The Toyota WS fluid was bright red and looked great by the way, despite using the truck to tow.
So, even though I am a little OCD about fluids, the conventional fluid was holding up just fine in that application.
Just because something sounds better, or costs more, doesn't mean that it makes sense to use it.
*I've owned over 25 cars, and I have yet to blow up or replace a transmission. Done a few clutches along the way. I listed the cars that made it to 200,000 or more. I still own two of those listed. They're still in daily use. Most of the others were sold, or totaled, before reaching that number but the point remains: every single one of them ran fine on conventional transmission fluid.