Even on the extensions platform, there's no basic option to blur a texture/image in shaders. Why? I just cannot fathom, it is one of the mostly widely used graphic effects in the entire history of film and digital media.
First, texture images can be blurred using softing/sharp brushes in either image paint mode or texture paint mode in 3D view port.
Second, renders can have motion blur and additional blur options using blur node in compositer.
Third, there is a blur effect in the VSE that can be applied to strips.
I'm not sure why a blur node in the shader editor would be needed. You mentioned graphics effects and film. Those are covered in the compositer and VSE
***Edit***
There is a blur effect at the seams, but it is called blend on the image texture node.
