So you won't even dare make predictions? What a surprise.

I use VGC just for Europe because there's no other source for Europe numbers. I use NPD for U.S. and Media Create for Japan. And the PS4 is in fact behind the Wii in the U.S. and Japan based on NPD and MC numbers, respectively, and will likely depend on Europe to make up the deficit that will almost certainly be remaining by the end of the PS4's life cycle in the U.S. & Japan.

Here's my optimistic scenario for PS4 sales through to the end of its tenth full year assuming a 2020 launch for the PS5.

So, that's 110-115M for an optimistic scenario.

Pessimistic scenario: 95-100M.

Median scenario: ~105M

Now, I'd be pleasantly surprised if the PS4 was down by less than 20% next year, but if this really is the peak year, then given past post-peak drops 20% is likely.

People who say never should answer these questions.

March 2018: 1

March 2018: 1

March 2020: 1

March 2021: 1

Pessimistic scenario assumes 2019 launch for PS5 and/or steeper than expected drop-offs in 2018 vs 2017.

Last I heard, Sony was projecting 78M shipped (not sold to customers) by March 31, 2018. That's 18M for the April '17 - March '18 period. I'm thinking 72-73M sold by year's end, and maybe 75-76M by the end of Q1 2018, consistent with Sony's shipment projections. Assuming the PS5 is announced in the first half of 2020, that gives them roughly two years, give or take, to sell another ~25M units to pass the Wii before the PS5 is announced. Possible? Yes. Likely? I'm not so sure.

I think 2018 will be down YoY, that is unless Sony is able to retain sales momentum through big permanent price cuts to both the base model and Pro this holiday, and even then that might not help. As a system ages, it is faced with the reality of dwindling numbers of new potential customers. At some point, a system will pass its peak, and nothing, not even price cuts, will reverse the decline. Price cuts have proven to have greatly diminishing returns later in a system's life. The PS4 has already sold almost as much as the PS3 & 360 had done when they peaked, and they had very late peaks compared to the historical norm and thus greater LTD sales at the point they passed their peaks compared to past systems (and the Wii). The PS4 is approaching a saturation point, and sales cannot continue at current levels for long. 2017 could very well be the peak year if it continues to be up YoY, but I honestly doubt 2018 will see the PS4 maintain significant momentum. If it does, it'll be setting an entirely new precedent.

Until next year rolls around and proves me right or wrong, I'm still going with ~35M in NA, ~10M in Japan, and 40-45M in Europe for lifetime sales, putting it at 85-90M in the three main regions, leaving the rest of the world to pick up the slack. RoW sales could be between 15-20M, so 100-110M lifetime globally, in keeping with my median estimate.

In May of 2002 Sony cut its official price of the PS1 to clearence-like pricing of only $49/£49 MSRP.  

That was a cut of 1/6 of the PS1 launch price of $299.  

An official price cut of 1/6 of the launch price doesn't happen very often, if at all.

Without it's official $49/£49 price points the PS1 likely would not have crossed the 100M mark before the end.

To put that in perspective most other new games at that time were also $50 or more. Conker's Bad Fur Day launched a year earlier in March of 2001 on the N64 for a MSRP 69.95 USD.

So the PS1 was effectivly as cheap as a new game (or cheaper) from 2002 onward.  Buy a disc/cart game, or for the same price buy a console with controller.

This is the stuff betting dreams are made of. I went through this thread and read most of the posts the two of you made. These are my propositions:

 Dulfite: 6 months of avatar and sig control that you are wrong in your prediction that the PS4 will sell at least 20 million less than the Wii, and another 6 months that you are wrong that it won't outsell the Wii.

Teriol: You seem very confident that the PS4 will fail to outsell the Wii. So, same deal as above. If you are correct, you have 6 months of avatar and sig contol over me, if you are incorrect, I have six months of control over you.

I'm a big, fat pig, and I want to slovenly, drool flying through the air, feast on two ripe melons.

Because the Wii is dead and ~101.2M is as high as it's going to go. And we're talking about when the PS4 will outsell the Wii, not outship it, and I don't think that will happen before the PS5 is announced, assuming it's announced in 2020.

Or are we talking about when the PS4 will pass the Wii in cumulative LTD, not when it passes the Wii's lifetime sales?

Whenever anyone talks about sales - 3DS has sold this much etc., it is always shipment numbers. Sony is the only one releasing sold through numbers and even then that's done only for the PS4 and done sporadically. When people are comparing sales, they are comparing shipment numbers. We always, always use shipment numbers.