Ever listed a vehicle on Craigslist? Sellers get deluged with lowball offers all the time. Why do so many people bother with lowball offers? Because they work. At least some of the time. And even sellers who reject lowball offers know to build in negotiation room in their asking price, because haggling is how it goes.Ebay is more like Craigslist than a car lot.
Fine, but members here regularly post about getting deals on Ebay as good as his original offer or better, via the offer system. There is absolutely no reason, him not knowing you from Adam, for him not to make the attempt or for you to respond with a snarky "really?".