Do people really just not get it that their items are not selling...

What Music Room sells appears to be mostly overpriced, sure.
My impression regarding haves and have-nots among those who participate is mixed and complicated. Besides, I think that some are just not in the mood to buy for various reasons. But that's active participants. Perhaps many sales go overseas especially to Asia. I also see some good 220V equipment from overseas dealers that no-one buys for months, some priced reasonably but still quite expensive. But you are right, $2k for old piece is already a lot of money, certainly for me.
Overall things don't go well, no doubt.

Having no problem as I'm giving great deals everybody is jumping on my stuff.

At some asking prices I’d rather buy new with warranty.
For me the warranty is worth at least 25% of the new price.
So the "like new" item has to be discounted accordingly.

@rja I agree.

I'm watching an item on eBay. Retails for $400 with free shipping. The item came up 2 or 3 weeks ago. Description says "new open box". $355  'buy it now' plus $20 shipping. Below that it says "don't try to low ball me, I've got plenty of time".

So he wants to sell his used item for $25 less than new from manufacturer with warranty.

Well, it sat there for a while. Now price is $310 plus $20 shipping. The remarks about low balling are gone. A few people watching. No one bidding.

But that's still only $70 less than retail with warranty etc.

I might bite if he gets down to $280.

However, I get his game. I see people buying used stuff on eBay at or just below new prices all the time. Rubes. 

N80
If you really want to have a chuckle just take a gander at what some loons buy gift cards for.
I howl in helpless laughter when I see idjits paying MORE than face value for gift cards just because they are too lazy to get off their butts and head to Target or BJ,s and get 10% OFF a gift card.
Too funny!