Most people want to build things not cores, the cores aren't the core competency. So the hope is, release what cores you have & let others improve it for you. Western Digital's swer-v core is seemingly an example of this thinking.
And the companies that don’t want to make it their core business but can afford enough resources (e.g. Google, Apple, Amazon) would just use them to leverage their core products.
I could only see this on the lower end where margins/required R&D investment are relatively low.