I've listed facts.
Then pointed out the only theory that actually fits those facts
Let's see where specifically you're jumping off my logic train.
Facts:
Tesla is now actively using two different rear DUs in Model 3 production, and was not for the first ~1.5 years of life where they only used the 980?
Tesla is still using the 980 in all P models, but now using the 990 in AWD models? Tesla is NOT using the 990 in any P vehicles at all.
Tesla has several times, including in explicit statements, made clear they abhor increasing manufacturing complexity or adding alternative parts without very good reason/need, and avoid doing so as much as possible... (again see how much nicer the SR interior is than it was supposed to be as but one of many examples of this being a fact).
Ok, so, those are facts- do you agree they are facts?
Once you have those, logic requires you to admit there must be a very good reason they're using the 990 in the AWD at all.
Now let's apply logic to the possible reason(s).
A) Lower cost, but lower performance- That certainly fits the existing facts at least. Enough lower cost in fact it's worth bothering adding complexity. And since it's ONLY going into AWD the lower performance is ok. So we can leave this on the "possible" reasons... agree to THAT much?
B) Lower cost, same OR better performance- We can easily eliminate this one. If that were the case it'd be in the P too wouldn't it? It's not.
C) Same or higher cost-same performance- We can easily eliminate these too...there's no reason at all for the 990 to exist if it was true.
D) Same or higher cost- higher performance- We can easily eliminate this one as well- It'd be showing up in the P (for a future Lud mode maybe), not the AWD. That is counter-factual to what is happening.
I can think of no OTHER possible reasons besides those listed above.
All but the first (A) are impossible based on the facts we have and can be easily eliminated.
Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.
And the truth in this case isn't even all that improbable. Much cheaper, lower capability, motor, going in the car they make/sell a lot more of, and which doesn't need the higher capability.
Otherwise the existence, and use in the AWD only, of the 990 does not make any sense.
Didn’t read past your first sentence.
You have a theory.
Prove to me with facts or evidence the 990 is cheaper or less capable than the 980.
That it exists is not factual evidence of its price or capabilities. To suggest otherwise, despite hundreds of words explaining your logic (which by the way I fully comprehend and is reasonable), is incorrect.