Steve. The ending of items early is to some extent eBay's own doing. The buy it now function with a maximum duration of 28 days has been replaced with an automatic revolving relist if not sold. There is no opt out of this so the only way to stop it if you want to try elsewhere (or go away on holiday as I did when you couldn't respond to a sale while abroad) is to end the item early. I sought eBay's advice before doing so and was told that's fine.
You can end a listing quite easily - particularly if it's listed BIN and on the automatic re-listing.
One of the options is - 'The item is no longer available'.
I have a small stock of camera desk lamps that I have listed both on eBay and Etsy but which I don't take to shows. If one sells on Etsy, then I end the listing on eBay no sweat.
I don't see any moral dilemma in ending a BIN early, it's no different to something being on the shelf in a shop - someone else could buy it, or the shopkeeper could take it off the shelf, it doesn't matter how many times you've been in the shop to look at it. On the other hand, I don't end auctions early; I have often declined to convert to a BIN mid-auction when requested.