I would also love to see a series 4, though I have no idea who that buyer would be. After Target and Walmart, who's the biggest bricks and mortar retailer these days?
In addition to Walmart and Target, Toys R Us also sold Wackys from the modern run (in fact, many of the ANS Bonus Stickers that were released within ANS1 and ANS11 came from Bonus Boxes that were sold by them), but they're
long since gone by now. The first two of these three stores are the only ones left that
could do it but, for unknown reasons, they've chosen
not to.
In fact, going off-topic for a brief minute, Toys R Us was the only brick and mortar store that
I know of that sold both of the Wax Eye Productions trading card series
Cereal Killers Series 1 and
Cereal Killers Series 2 back in 2011 and 2012, respectively (at least, that's what I've heard
somewhere along the line).