In cases where the price is nuts I just watchlist the item and wait for the seller to relist with a lower price. They usually do after a couple of relists with no bidders. Pointless messages would probably encourage many of them to hang on longer.
There are many shameless and cringeworthy tryers who message offering very cheeky buy now prices. No doubt they are successful often enough to make the strategy pay. I'm sure there are some that practically do it for a living.