If they ty to rush out PS5 in 2019 or 2020, I don't see it happening. However, if we end up with a PS4 Premium, PS4 Pro Slim, PS4 Super Slim, and PS4 Portable in 2019, with PS5 holding off until 2021 or later, than I have no doubt it will.

There is huge potential for growth a Digital only Super Slim with 500GB of Flash, as they should be able to reach the $99.99 price point. I think they should add HDMI 2.1 to all PS4's effectivly allowing this $99.99 PS4 to go head to head with Amazon Fire TV, Apple TV, and Roku.

The PS4 Portable would greatly improve performance in Japan. Being the first Mobile PlayStation with access to real PlayStation games, it would also have a real good shot at succeeding everywhere else as well. If they have a 4G or 5G model of the PS4 Portable, then there is even more potential.

PS4 Pro and PS4 Premium can continue to offer higher end performance for those that need no compromise 1080p - 4K in all titles, as well as better PSVR performance. 

I fully believe that Sony has the means to move 250+ Million PS4's if they expand the form factor to more sectors. If Sony plays their cards right, the PS4 should end up th highest selling gaming platform in every region.

I think two things need to happen, that PS4 could reach that mark:
1. Microsoft leaves the video game console market.
2. Since there is no competitor for high-end console gaming anymore, Sony has no pressure to release the PS5 too soon and therefore postponed the release of the PS5 by several years.

It really depends how long they keep supporting the console with games to warrant purchasing it. It's possible.

I think not. I don't believe they will delay the ps5 that much. Plus market saturation might be a thing

That's twice what it sold now according to that chart, I don't think that'll happen. It's been a good four years now, and it would be exceptional if it sold like it's selling for nine full years. I's say 40m is a decent and doable goal for it.

I doubt it will happen unless Sony holds out for a while before releasing their next console. That, or ps5 having a rough start just like ps3 did, which helped ps2 a lot so it could keep on selling for many years... That said, 3rd place looks like a lock, will probably end up between 45-48, Guess we need to wait...

I am ... not so sure that it will.

You're in my m mind ( albeit I don't rule out 50m ) , if it's financially viable for Sony ps4 price falling permanently 199$ ( I refer to 1tb ps4 slim ) , that would do wonders in Eu.

Europe is the most price sensitive market, the aging 3ds being cheap (2ds/new2ds xl ) making it to be going neck with neck with switch ( which has a higher price there than the USA & Japan )in some european countries for instance ) ,  as for the bolded, what it says should be taken into consideration by some people when they predict lifetime sales...

Its possible, i think. Would be very cool : )