Integration of Texture Streaming and Meshlets generation

More recently, Epic Games introduced Unreal Engine 5. Where are the new DirectX features offered by Nvidia: Mesh Shaders & Texture Streaming What allowed them to provide high-performance interaction with incredibly complex scenes without being tied to the limits of draw calls, creating LODs: devblogs.nvidia.com/introduction-turing-mesh-shaders/

There is material that describes the pros and cons of the proposed innovations. Why not integrate features that would help significantly improve the experience of interacting with large scenes and objects of high detail?

Especially considering that the presented innovations are also presented in the form of extensions for OpenGL and Vulkan: developer.nvidia.com/vulkan-turing