What is wrong with the quality of this shot?

Hello,

Did you use a tripod or handheld?

There is a problem with noise and artefacts -  it's noticeable when viewed at 100%:

The moon is a problem in terms of exposure - you have a messy white blob, unfortunately. 

Did you also apply some noise reduction? There is a lack of detail, and the pixels are somewhat smudged together - noise reduction does this! This would also give the appearance of being blurry. So, it's not so much of focus, but of using noise reduction I think.

The pixels are sort of smudged together.

The black areas should also have some detail in them

This appears to be a handheld snapshot, which would never work well under these lighting conditions. It's blurry and underexposed in general except for the moon, which is quite overexposed. You would have needed to shoot bracketed images and combine them in Lightroom or Photoshop to obtain a correct exposure throughout the frame.

Focus, overexposed moon

I'm looking at this on my MacBook Air, which doesn't have the best screen in the world, but I'm not seeing any one thing that stands out as being tack sharp. But if I'm wrong about that, the histogram is showing a lack of detail in the shadows and some burned out highlights.