Usually that's done when a seller is away on holiday or has no stock because it costs nothing to change the price on a listing but it costs something to list (as a business seller)
Also, search engines... Keeping the item on the same static item number means it gets crawled & remains a valid destination (albeit expensive) and not a "no longer for sale", but...
Further, once you've browsed there once, it hangs around in your eBay history... When the price returns to normal you may then be interested.