Prediction: PS6 won't sell over 50 million units lifetime.

[Norion]

It all comes down to just how long it takes till things get better. A really expensive PS6 would have low sales after launch but a significant price cut once RAM and storage get cheaper would help massively. Since the PS6 will be on the market for a long time I'd say over 50m is more likely than not though either way it wouldn't be surprising at all if it becomes the worst selling Playstation ever with the way things are going.