Yeah, someone on another site said maybe a mob dropoff point for stolen vintage cars... Or maybe a prewar stash (though I think there is some postwar stuff in there, too) that someone was hiding from the Nazis, lol. Lots of speculation.
Almost everything pictured is post war. A lot of them are from the 60's, a few are from the 50s and perhaps 70s. Only a handful of really old ones.
There's an awful lot of dust on those cars for them to have been dumped any time recently.