I actually predict the PS5 will sell around PS3 numbers 80-90 mil. For Xbox Series S/X I predict 40-50 mil. 

I don't know how or where you are getting this from. As it stands, unless the cheapest PS5 you can buy is $499, and there isn't a PS5 price at $299 by 2023. There is absolutely no indication today to suggest that the PS5 will not at the very least Bush PS4 numbers.

And this sentiment about PS4doing so well because of Nintendo and MS, is baseless; at least with regards to Nintendo. The Switch, as successful as it has been has not in any way impacted the sales of the PS4. So why should it or a switch 2 affect the PS5?

And as for MS, I would agree that because of how similar the two platforms usually are (PS and Xbox) one usually does well at the expense of the other. But that doesn't even really apply this time around and its something even MS has alluded to. I don't understand how anyone expects the Xbox Series to do so well considering how easy MS is making for you to not even have to own one.

Ok... so you predict the XSX/S to sell about the same amount as the XB1... and predict that the PS5 will sell 20M - 30M consoles less than the PS4.

Basically, you are predicting that coming off the PS console with the most momentum a PS console has had since the PS1 - PS2 and the PS2 - PS3, the PS5 (barring any $599 surprises) will do only as well as the PS3? 

Thats interesting.

For the Xbox Series S/X I think the S and it's price point will really help get a lot of sales. I think if the price point and marketing is on point it can bring Microsoft back to winning NA and grab some of the EU market. I even think they'll do better in Japan this time (which isn't saying much). With that I believe it will sell around Xbox One numbers.

For PS5 the reason I think it will sell less is that at the start of the generation Nintendo and Microsoft stumbled and Sony just capitalized, which lead them to essentially becoming the "default" console. Since Microsoft and Nintendo are in much better position I think it will hurt Sony. On top of that PC gaming has become way more popular now than ever before which will lead to less console sales. Japan is done with game consoles, so PS5 will not sell as well as PS4 there (I predict 6-7 mil). Game streaming I think will become more mainstream in a few years, which won't help. All of that is why I think PS5 will be around PS3 numbers. 

Of course I could be wrong and the PS5 will do 100 mil and the Xbox Series S/X will do less than 40 mil. This is just all predictions here just like with the Switch where some thought it would fail. I predicted it would do over 100 mil and it seems I'll be right on this one. 

I think it depends on how Xbox does, and maybe how their xCloud streaming thing evolves.

Right off the bat PS5 is entering a market where Switch is blowing away everything that has ever existed other than DS. So that is a very different situation than entering the market with a botched Xbox launch and a failed Nintendo system. Switch doesn't compete like super directly with Xbox and PS5 but still a lot of those gamers overlap which means that's money that has to be shared between Switch and one of the other two. Now maybe that just takes away PS5 games but doesn't do much to hardware sales, I dunno. But either way PS5 is launching into a much more competitive market than PS4 launched into.

As long as Sony doesn't botch something like a super high price or if Microsoft doesn't do something amazing PS5 should sell above 100 million again, though I doubt it'll do PS4 numbers unless Xbox really fades. PS4 got over 3 years with a stranglehold on the market, PS5 might only lead sales for two or three years during the next Nintendo transition and likely won't dominate any years except perhaps Switch's final full year.