Game! - Where the stick is mightier than the sword!

I'd like some way to see from the financial advisor what items either did not sell, or what prices you put something up at that was too high.

We can see highest price paid.
We can see average price of things that sold.

Nothing seems to indicate things put up and not sold.

Ideally, some sort of histogram of prices offered/sold, but that might be too much work.

There is "What percentage of each item sells?" and "What percentage of each item type sells?", which largely addresses what you're asking here, although it doesn't factor in price.

How about a graph of (average sale price)/(average listing price)?

How about recent average sale price vs recent average listing price?

Lifetime average includes a bunch of cheap stuff before you learned better.
Recent average shows the stuff that matters when trying to tell if you're too cheap or not.