Flashes are history. They are of no particular use to anybody any more so why buy them?
The proof of the pudding is in the prices. Years ago, a really good flash would command a really high resale value. That's history. Nobody wants to buy used flashes even at half price now. An unused flash that just a couple of years ago cost over $550 won't even go for $275. This flash (some of it is still in its original plastic wrap even) has been advertised on Craigslist, eBay and Amazon with zero enquiries and zero takers. There has been zero interest. It doesn't matter what the price is. Nobody seem to care enough even to look at the adverts. The hit counters remain at zero. That just seems strange when a range of sale prices have been tried and identical secondhand units advertised in exactly the same manner seem to go for a lot more.
Could it possibly be that the economy just sucks and people are no longer prepared to buy equipment? This is a definite possibility. Reportedly the camera companies are struggling with Digital SLR sales plummeting amid stiff competition from smartphones, zoom compacts and the new mirrorless interchangeable lens cameras.
In the meantime, there are two of these flashes for sale and nobody seems to be paying the slightest attention. It has become such a waste of money advertising on eBay and such a waste of time advertising on Amazon that they're now occasionally advertised on Craigslist and left in a storage unit. Eventually that storage unit will probably be cleared out and if they're still there, they'll probably just get tossed in the garbage.
What on earth has happened to replace them? Camera manufacturers have been producing for years cameras with ever higher ISO. Higher ISOs have become freer of digital artifacts with the end result that they can be used without a flash.
This photograph was shot at 1600ISO, hand held in a very dingy night club. The actual exposure was 1/25th and the picture is not bad at all. Give that an ISO from one of the newer cameras of 128,000 and that exposure would have been 1/200th of a second. Use the latest of 256,000ISO and that's 1/400th exposure - enough to freeze even fast motion. Are flashes now just an anachronism dating back to the days of old when pioneer photographers used to pile magnesium powder into hand-held flash units that they would ignite manually.
Given the current high ISOs, it makes sense that flashes are now of ever less demand. It would further make sense that ever lower powered flashes are needed. Indeed, the simple LED flash on many phones which illuminates a scene so well could end up being the preferred method of illumination for digital SLRs. Already Canon has at least one flash with a built-in LED modelling light.
LED flashes have a lot to recommend them to be honest. They're small, low power consumption and they are fast. Typically the fastest flash from a standard unit is about 1/38,000th of a second. From an LED that could be as low as 1/1,000,000th of a second. A flash like that, assuming decent output could well freeze a bullet in flight.
Now why exactly are the top of the range Canon flashes not selling secondhand? It's hard to say because LED flashes have not yet been developed for DSLR usage. Not everybody wants to use high-ISO images with grain either. Is there something wrong with the advertising? That's unknown as the wording is copied from adverts that apparently sell. What is the issue? Unknown. All it means is that there's $1100 of electronic trash taking up space in a storage unit.