I believe this to be the case as well, especially when we see new proprietary fluids.[/QUOTE
Let me try this again, I don't think I explained it right.
I'm gonna use the WS fluid as an example. When the Toyota engineers designed the new internals for the transmission they came away with some new materials that needed a different type of fluid that was not manufactured at that time. Did they start with the intention of a new fluid from the start? Who knows. Once they determined the fluid they needed they start the outsource process. They tell the fluid engineers I need a fluid that can do ABC. Of course this is not on all systems in a car. The power steering system really has not changed in regards to what fluid it takes.
Same thing as when the manufactures started designing engines to use a lighter weight engine oil. 5W30 was the standard for quite some time. The fluid engineers and the auto engineers came up with 0W/20. The fluid companies do not make a product and say to the car companies, Ok start producing systems to use this oil.
When Toyota changed the band material's to use Type T 1V fluid they had to get a fluid manufacture to produce it. I remember for awhile that the only place you could get that fluid was at a dealer. There is a difference in the transmission's operation when you do not use this type of fluid, believe me.
When GM/Allison came out with a totally new transmission assembly you could not buy that fluid anywhere else but at a GM dealer. In the contracts I am 100% positive they state how long the fluid manufacture has until they release the specifics of that certain fluid. It's all about the almighty dollar, it's what it all comes down to.
It's actually pretty interesting how all the different parties involved play the game. I just wonder how much Exxon/Mobil pays these car manufactures to be the 1st one to have a certain fluid available aftermarket. I just used Exxon as an example. Sometimes it's Amsoil, Castrol and etc.
Here is an interesting article about the use and sale of OEM fluids and such.
http://www.aftonchemical.com/Insight/KnowledgeCtr/Research_Trends/Documents/ATFspreads.pdf