Not true, for several reasons. First, because a better lens may not only be sharper, but may also render with more pleasing contrast, reject flare better, and provide any number of favorable characteristics that a lens is capable of producing - besides just sharpness.
Second, sharpness can be made less so, but not the reverse.
Third, if a photographer wishes the photograph to be sharp, then a sharper lens is better than a less-sharp lens, always.
A lot, if you're a sports photographer or standing where Zapruder was with his movie camera.
Because it is frequently desired in a photograph - and again, a better lens can render less detail if desired, but a poor one cannot render more.
And that is why photographers who have to make their living by their equipment always buy the worst. Right?
You're right, I've never seen a NASA photograph enlarged and hung as art in a home. Oh, wait, I have. Whoops.
Yes. And if the photographer is trying to do something which is beyond the capability of their camera, then a better one would do that particular job better. Which makes the answer to the question "Is it the photographer and not the camera," a solid 'no'. It is both, which I said.