This shows the core of the flaw in the argument.
"The tool is great. If the result is not perfect, it is the user to blame."
It's unfalsifiable. The LLM can provide terrible results for reasonable prompts, but the response is never that LLMs are limited or have flaws, but that the user needs to prompt better or try again with a better LLM next week.
And more importantly, this is for the good case where the user has the discernment and motivation to know that the result is bad.
There are going to be lots of bad outputs slipping past human screeners, and many in the AI crowd will say "the prompt was bad", or "that model is obsolete, new models are better" ad infinitum.
This isn't to say that we won't get LLMs that produce great output with imperfect prompts eventually. It just won't be achieved by blaming the user rather than openly discussing the limitations and working through them.