I believe they have already listed that neo geo pocket station item in the past. And they have had it for many years now. Granted, it is a unique item, as for what it's worth, I guess the open market will decide. He may have started the auction at 14K just to begin somewhere. If it gets no bids, he can then relist it, lower to 12K, then 10k, whatever; eventually someone will meet and start bidding at some price point. Totally normal for someone looking to get top dollar and consistent with someone not in a hurry to sell.
As for the modem, I've seen pictures of it before, but none of them looked exactly like that. Not sure what to make of it. In the item description it mentions images on screen and such, would be interesting to see what they show & what the game ID displays in a uni-bios or debug console. Again, the listing & the asking price all within his rights as the seller.
Now, to be critical, who attempts to ask for 14K in an eBay listing for a "super rare collectors piece for a now booming gaming hobby" and provides ONE picture; which doesn't even show the item plugged in, turned on, and doing what it claims? What buyer wouldn't want to ask & see more? (same point with the 5K modem item)
Lastly, yes, it's great to see him reference "Warlocks" and "Dunk Star" protos in his listing, and by all means, if they do get listed, that's awesome indeed. But, that is not the first time they have made similar statements whereby claiming to be "coming forward soon" with additional pics & info of said items. Nothing ever came back then, so I'll hold back my excitement for now. Let's see what happens this time around.
Either way, no need for drama on this yet, let them say and do what they want, so long as it can be backed up. Time will tell.