As I've always said, above PS1, below PS2.

There are a lot of loud Nintendo and Xbox fans(last generation ps3vs 360) zooming around the internet who likes to beat down the sales of ps4 as if it somehow makes their console look better. The reality is ps4 is the king this generation. I think 2019 sales will be 17million; 2020 sales will be 12million. So back to your original question, that's 123million in sales. Probably another 10 million after 2020; so lifetime sales of 133million. 

130m-140m

The eventual $199 price tag for the base system will give it another huge year in 2020, but i think it will die quickly after that because the PS5 and Xbox Next will be far more competitive successors with full BC, bigger titles out the gate (TLOU2? Horizon 2) a decent entry price & of course the peak of the Switch. I see these factors killing the current gen consoles at an abnormally fast pace.

That would be the most likely scenario..... 

No.... this is not 2006 and the PS5 is not going to be a $600 console in a space where there is a cheaper $400 console available.

I cant stress enough how important this is.

The people that buy in the first year mostly are the early adopters. If the console comes in at $399/$499 and is BC with the PS4 then all those early adopters not only have no reason to wait before buying they also have no reason to hold onto their PS4. Especially when you consider most will be in a position to trade in their old console.

No matter how much sony drops the price of the PS4 buying used will still be cheaper, and there will be a lot of used consoles up and about. That is going to really impact hw many new PS4s sony will be able to sell at that time.

I principally agree with the Original Post but the answer depends on which year we take as the end of the console cycle. Most people forget that the current sales of the older consoles are usually not the total sales when the newer generation arrived, but they rather continued to sell for a few more years, which is especially true for Nintendo handhelds and Sony consoles. PS2, for instance, sold around 30-40 million after the release of ps3. So PS4 will continue to sell a few more years even after the PS5 comes out. It also depends on WHEN the PS3 will come out. Assuming it will be released at the end of 2020, we still have two more full years before release and probably 2-3 more years on extended support at the very least.

Sony themselves estimated that the PS4 will sell around 19 million this year, and assuming a further drop to 15 million in 2020, it will sell about 34 million more by the end of 2020, bringing the number to around 94 + 34 = 128 million, or let's just say 120-130. This is by the end of 2020, already surpassing PS3, and PS1. If it continues to sell about 10 million annually for 2-3 more years, it may reach the PS2 numbers.

Take a look at my ORIGINAL DETAILED SEMI- ACADEMIC ESTIMATES back in 2014 for PS4 and XB1
=> Summary, I had estimated, by 2020, PS4 would sell: 120-150 million, and XB1 :41-64 million
=> Yes, the ranges are a bit large but still CORRECT, and there were a lot of unknowns in 2014 (5 years ago!)
=> The 2014 estimate was predicting a minimum of 120 million sales by 2020 end, so yes, it will pass that point in 2 years. http://gamrconnect.vgchartz.com/thread.php?id=178341&page=1

Most don't realize that other regions don't have viable sales until after the next console has launched worldwide, and many are still on PS3/XBOX360 and will switch. Thing will leg for years.

If PS4 for Calendar year 2020, 2021, 2022 and 2023 ships an average of about 11m a year over the 4 years then it will be at 138m by the end of 2022. Certainly possible but depends on the price Sony goes with.

130M should be what it achieves.

I think the biggest thing MS would screw up for PS4 sales, with multiple next gen XB consoles, would be Pro. If PS keeps selling Pro alongside PS4, with a single $399-$499 PS5, people who decide they would prefer the best PS4 model, would have to choose between a $299 Pro or $299 'XB2' base model with XB1X like specs. PS4 has the brand name and games behind it, but it's old tech in comparison to a next gen XB. Which is the consumer going to choose in a tech based age? Heaven forbid PS drops PS4 and only goes with Pro in a similar scenario. PS would be forced to sell Pro at $199 or $249 against a next gen base XB at $299. Pro at $249 for a year maybe, and then $199 beyond that, could be a really enticing draw though vs an 'XB2'.

As for a $149 XB streaming box vs a $199 PS4, odds are the majority of sales will still go to the PS4. Both that streaming box and base 'XB2' would be eating into late PS4 sales. That very easily could be at least a couple million less console sales each year for PS4. It's not like next gen XB would cause PS4 to tank, but in terms of overall sales, it will have an effect.

*Mind you, further thought makes me think dropping PS4 and going with Pro at $199, could actually solve both these problems the best. That way PS only has the Pro and PS5 on the market, and the Pro is way better value than the streaming box for slightly more, but a strong enough last gen console, for cheap enough, to mostly stave off the base 'XB2'.

PS3 outselling Wii wasn't too crazy.  I mean, its sales were starting to rise, while the Wii's were starting to fall, and it finished just ~15M behind it.  My guess is they were expecting the PS3 to have better legs after the PS4 launched, maybe match the PS1's ~20M after the PS2 launched.  Two things stopped that, though.  One, the PS3 was already 7 years old when the PS4 launched, and two, Sony wasn't able to get the price any lower than $199.

I don't know.  I don't really see it dropping as much as ~27% this year.  Not with some big games still launching and, more than likely, a cut to $249.  I'm going to go with a drop of 15%, or 15M.  But, we shall see.

That's quite the range.