Usually if the seller sets the vacation flag on their account, a notice iz prominently displayed at the top of the listing page to the effect "this seller isnaway until (month, date). If you purchase this item now shipping may be delayed". That's not verbatim, but close enough. I see that in both desktop and mobile versions of ebay when I'm looking at stuff there.
I think the sellers all drop shipping from a common supplier may not be all that far off the explanation. Rather I suspect the sellers are all either the same - or affiliated - party runnning multiple accounts with listings for the same item. Are any of the photos identical across different listings? Still can't figure out what the point is, especially if the items cannot be purchased and no payment is being collected.
Which brings me to another oddity. Sellers in Japan listing gear (Sansui, since thats what I'm looking at, mostly) under multiple accounts with the same photos - frequently from some sort of resale shop - but usually having different prices. Most of the time the prices are fairly close, but in other cases one listing will have a much lower price (usually BIN) with a massive shipping charge and another near identical listing will have "free" shipping but that figure will be close to the combined total of the first listing with the shipping cost seperately broken out.
I can't figure out the rationale for this approach. Doesn't look like any kind of scam (what is the possible benefit to the seller?) Further, these are generally items rare enough that there is no apparent need to load the search results with multiple hits to benefit one seller over others offering the same item.