What is the average dealer mark up?

Well bob540, you are clearly not a B&M customer, you said: "I want retailers to be able to stay in business",  right why? So you can take up their time for free? Listen to gear you might be interested in to purchase elsewhere? Just so you know, savvy dealers can spot you out in just a few minutes if not sooner. Please don't bother B&M dealers, they will be fine without you, by used or online. 

hmm. “most audiophiles aren’t really that good at listening”’etc. that’s a very arrogant statement. just saying.

Quick add to my post so you numbers guys can see it in text:

SONY TV's (Trinitron) were THE MOST POPULAR in the world at one time--it was a great TV.  The dealer cost was 80% of the FIXED (these were the days of "fair trade" pricing where you were legally required to sell at the manufacturer's price or lose the line, period.  No second chances, and they "shopped" you pretty much every week.)

Fixed overhead at my shop was 21%

You numbers guys figure that one out, OK?

So much "profit" I could hardly spend it all when I sold a Sony...