Subaru sells crate engines, even entire drivetrains. I’m aware of several specialty vehicle companies that use them.
The Sube flat four is an excellent engine, springboard off of that and cost of development would be considerably lower.
Move to manufacturing drivetrains after the vehicle is established and selling.
Agreed. However, even tho’ we really like our (several years old) Outback, even Subaru does things that “bug” me. The fit of the engine in the engine compartment is so tight that just changing the plugs is a major endeavor. The front seats area is too confined / cockpit-like too — and my wife and I are not big people. My old Honda CRX was more spacious up front, by far.
That said, comparing our Outback to the model-year later Explorer we got to tow heavier loads is remarkable. The Explorer design in many ways is just flat out sloppy. (Wasted space, exposed cables in the passenger compartment, etc.)
But, to your point, Subaru does make good drivetrains: Would they sell to someone they perceived as capable of becoming a significant competitor? And do they have the capacity? Last I heard, they were struggling to keep their own dealers supplied due to their growth in sales.
(I really believe the growth figures — Outbacks are proliferating in even our area - the Mid-South - like rabbits!)