Sony didn’t tell any third party developers about the monster 8GB GDDR5 RAM in the PS4, until Sony's PlayStation Meeting 2013. When they made that announcement, those that didn’t have the latest dev kit thought that they would only have 4GB of RAM, still a very significant amount.
Just Add Water's CEO Stewart Gilray said: "We were told [PS4] was 4GB
originally," Gilray told us, "and we first knew it had 8GBs when Mark
said at the event's stage, 'And it has 8GB of memory.' We'd had kits at
that point for a good while. It's a fantastic amount of memory, especially DDR5
memory, because it's so fast you don't have to have everything there at
once. You can swap it in and out instantly, effectively. But when they
said 8GB it was like, 'Ooookay.'"