Jolla is very much in survival-mode. Their priority is to build a sustainable business. Making Silica open source is not aiding that sustainable business in the short term.
Be aware, making software open source involves a lot of work. You don't just throw stuff over the fence and be done with it. You need to maintain it, review and apply patches, answer questions, write docs. That doesn't come free, and doesn't help the cause of surviving in the short term.
Just look around at all the businesses that have failed to make a sustainable business out of mobile linux phones. Ubuntu Touch is dead, and forked into UBports. Firefox OS is dead, and forked into something else. Purism has a good marketing team, but they are just starting. It is not easy to create a sustainable business out of this. And users are very critical and often demand feature parity with iOS and Android.
You need to maintain it, review and apply patches, answer questions, write docs
I don't understand this. None of that is necessary at all in order to release the source code. Just make it available to download. Heck, you can even "protect" it (nominally) with a download code that you ship along with the device, like you find with music.
Be aware, making software open source involves a lot of work. You don't just throw stuff over the fence and be done with it. You need to maintain it, review and apply patches, answer questions, write docs. That doesn't come free, and doesn't help the cause of surviving in the short term.
Just look around at all the businesses that have failed to make a sustainable business out of mobile linux phones. Ubuntu Touch is dead, and forked into UBports. Firefox OS is dead, and forked into something else. Purism has a good marketing team, but they are just starting. It is not easy to create a sustainable business out of this. And users are very critical and often demand feature parity with iOS and Android.