If you check the seller's auctions, past and current, plus his feedback, it would seem like he's never sold or listed a single diecast before these, so it is quite likely that he doesn't have the faintest clue about the values of what he's trying to sell.
He's probably heard of how old toy cars can be extremely valuable, so looking at his, he feels that they're "really, really old" and "in good condition", from well known brands, so, a very simplified logic tells him that they must surely be among those "extremely valuable" ones.
So what do you charge for such an item? You know how kids sometimes juggle with absurd numbers, not having any idea what these numbers/sums actually represent. "Okay, you can borrow it, but if you break it you'll owe me two billion dollars"
"Nah, that's not fair"
"One billion then?"
"Okay"
The prices of this seller seem to have been 'constructed' this way. The cars are 'really, really valuable' so one has to think of a price that sounds like a lot of money and this was the result.
This sounds like the opposite end of an equally clueless seller finding some toy cars in an attic, and thinking they're just "old junk", then pricing accordingly. In other words: our dream scenario