The PS4 is one of the best-selling game platforms of all-time. It's currently sitting at about 117.02 million units sold. During the Week of 01 Apr 2023 it sold about 3,700 units. It will likely get discontinued globally at some point this year, or at least in 2024 I would think.

PS4 helped Sony immensely after the massive amount of money lost by the PS3 and the failure of PlayStation Vita. In the U.S., PS4 Slim and PS4 Pro never got price cuts. I understand that the Slim goes on sale at major retailers at least yearly for around $200-$250. But that's not the same as a permanent price cut. The PS4 Pro had some good deals at times as well but maintained an official price of $399.99.

There of course is the Global Supply Chain Crisis which seems to have hurt PS4 sales more than helped. While more people spent more time indoors playing games, PS4s were tougher to produce and so were PS5 consoles (Sony's priority).

From where the PS4 is sitting right now, it's effectively finished in terms of units sold. It might not have 250,000 units left in it at this point. 

How Much Could PS4 Have Sold Without the Global Supply Chain Crisis? And is there anyone who thinks it would've sold less without it?

Probably not more than another million. I think the PS5 is what killed the PS4 sales.

I think it would be anywhere from 125M - 130M right now if Sony had PS4's during the lockdown period in 2020.

Probably wouldve reached the 120m mark, but I wouldnt expect it to go much higher than that.

I doubt it would've made much of a difference. IIRC, PS4 components were much easier to come by than PS5 components. That's also why it was so easy to find an Xbox Series S throughout 2021 over a Series X because the Series S uses much easier to obtain components.

Sony most likely saw demand was stupid high for the PS5 that they decided making too many PS4's wasn't worth it.

It's not like PS5 and PS4 share components (not the hard to come by parts anyway) so I don't think that had much impact. I think Sony just thought MS would be stronger this gen and decided to not give the PS4 a longer tail, they wanted everyone transitioning to PS5 as fast as possible.

Now today of course we know MS' software pipeline failed miserably and they haven't been to release 1st/2nd party content on time, but you'd have no real way of knowing that 3-4 years ago. 

If they had higher production and choose to lower prices abit? probably a good bit more.
I felt like they didnt give it the legs it deserved, as soon as the PS5 was about to release, they just left it to go out, hard and fast.

Surely more about 125 mils.
Without the global supply chaos in it's last full year before next video game consoles coming - with no doubts now would have more numbers.
Still impressive, even if it's Switch have higher records.

Not much more than we are seeing, the legs of the PS4 plummeted drastically once the PS5 got all it's material revealed and was set to release.

It's hard to say since it was mostly Sony's decision to let it die off by not producing them anymore. Of course the supply chain crisis had some part to play in that but it think they also just wanted a quicker transition this time around and would rather have people buying their new system than the old one, especially since the new one could do anything a PS4 could do anyways (except fit in my TV cabinet).

The pandemic defintely also boosted PS4 sales for a while in 2020, so all in all I think realistically it would at most have done a few million more, ~120m maybe. However if Sony had just kept on producing them maybe it could have reached 125m.