Having been on the flip side of this divide in the past, there really are a lot of potential safety and reliability problems when using random third party versions of components. While I'm sure there are strong financial incentives to constrain supply, there are also some other strong reasons as well.

Also it's very expensive to actually make an ecosystem compared to a close one. The best way to incentivize manufacturers to do it is by creating a competing product that is open and having that differentiating feature drive sales away. That's generally the approach that works best.