An average RAW you can turn into a good shot, a good RAW you can turn into a great.
The quality of what you start with makes all the difference.
To add:
The sharpness of a lens is its ability to resolve detail which implies an average lens will resolve less detail than a good lens. Even with all our sharpening options in post, we can only sharpen what is there. The detail the lens could not resolve is blurred and can't be sharpened.
The same goes for lens contrast (which depends on the ability to resolve detail). It's not just about overall contrast but about every individual aspect of the shot (micro-contrast).
Processing only enhances what is there.
It's not too different from shooting with a CPL. This far it is impossible to get the same result in post.
Every enhancement that can be done in post to a lower quality RAW can also be done to a higher quality RAW which results in the lower always remaining lower in quality. It's impossible to get it "as good" since that would require there to be a limit to how much we can enhance something.
Here's some article explaining lens quality to a degree:
Camera Lens Quality: MTF, Resolution & Contrast