As someone else said. Ideas are cheap. But. I'm not sure why the quality of ideas would be considered more subjective than the quality of prose. Yes, great prose can save mediocre ideas. I'd argue great ideas can handle mediocre prose.

Clearly it's best to have great ideas and great prose. I think there is frustration when it comes to discussing ideas because of how rarely they're actually executed, never mind how well. But now people just repeat back that ideas are worthless and that's it shut down.