Why doesn't unity support double sided shaders natively

Double sided shaders are useful and needed in many situations. AFAIK there is no standard, native way of doing it in Unity. You need to find or write a custom shader for this.

Unity has integrated so many features, assets to the engine and to the editor when they see that developers need and use these tools; like Text Mesh Pro or Pro Builder... Why don't they do the same for this very common need, why don't they support double sided shaders natively?

Am I missing something?