If Sony releases another handhled, it has to replace their Xperia devices. I would expect both a Wifi only model, and a 4G or 5G model with full cellular support. I don't think Sony will go the Hybrid route, but rather create an ecosystem of products that all share apps, games, and services. PS4 is on its way to either being the #1 selling console all time, or coming in very close behind PS2. The time of dedicated consoles is over, but the future of set top boxes will be much larger.

Going forward, I fully expect the PlayStation ecosystem to encompass all of Sony's products. Unifying there Smartwatches, Smartphones, Smart Speakers, Consoles, Handhelds, TVs, Cameras, and Car Audio under a unified PlayStation ecosystem is the only logical direction going forward if Sony is to remain of any significance in the consumer tech industry.  

No it's not? It will probably sell 18 million and then have a great year again next year(if it's lucky it will sell about 18 mil for three years in a row) and then it will start going down. It's going to beat Wii numbers, that's not even close to being the best selling console.

Sony doesn't have any magical technology, something that was 1/4th a PS4 still would consume 20+ watts of electricity and that would run for like 10 minutes portably at full tilt. 

Nvidia is as good as it gets and Nintendo's got them. 

Brand "loyalty" between Playstation/XBox is highly tenous IMO, don't confuse these types of fan boy boards for reality, in reality IMO XBox/PS gamers don't really give a shit about the difference that much, they just want the best versions of the big multiplats and will switch on the turn of a dime. They have no loyalty that specific to Sony or MS, they're basically interchangable brands, this gen Sony got off to a much better start and that snowballed because you don't want to buy the console your friends don't have and not be able to play COD/Madden/GTA/Star Wars online with them. It's not "brand loyalty" as we saw many of the same people drop Sony like a bad habit during the 360 era. 

The problems is that Switch was designed with that in mind. So it uses cartridges with just a few GB. PS4 games are easily around 50GB. And they have huge patches. I've just reinstalled Star Wars: BF since the season pass is free now and it greeted me with a 20GB patch.

Since we don't have any kind of cartridge this big, a PS4P would need storage enough to keep at least a few games, so I would say that you would either need a 128/256GB internal memory or people would have to buy big SD cards. Ok, a 128 GB MicroSD is around 45 bucks, so they could bundle one of those.

Sony would also have to figure it out a way to let people use their physical media with the PS4P. I doubt they would put a BR drive on it, so they would have to do some kind of method to allow you to registrate a physical disc with a PS4P unit.

It's not impossible if they manage to create a APU that's around half the power of the current PS4 (but with the same CPU) but scaled down to use less than 10 watts, that is normally the maximum TDP for a tablet form-factor.

Yeah and Nvidia just released Tegra X2 which is twice as powerful or twice as efficient as what's in the Switch, what Nintendo does isn't representative of what Sony will do. When you leave out the expensive joy cons and dock it's a much cheaper handheld than it's retail price.

I think your assessment of brand loyalty might be true for the US, gamers switched from PS to Xbox then back to PS, but anywhere else in the world it's wrong, it's pretty much been PS for the last 23 years. The Xbox brand is almost non-existent in Europe and other places, that's why Xbox will never dominate gaming because it's not a global brand. Xbox is/was a console for the American market and it's being beaten badly by PS4. Besides, considering the digital libraries people built this gen, many people will not jump brands anymore. This is the first really important digital gen.

Most important thing are the games. So long as MS doesnt have anything substantially better to show, it will still get beaten by even the Switch. It's not gonna matter when PS5 is 12Tflopz and nextbone is 14tflopz, the difference is negligible. You will see next gen play out between XboneX vs PS4 Pro sales in the coming years.

I don't see it. Sony and MS have attracted a userbase that looks out for the next jump in power. And they can live good with that (well Sony can, I can see MS is more experimental or drops out). Making a hybrid PS5 would be a massive risk for Sony: what if MS puts out a powerful machine and takes over all the fans of the PS system that like this power.

Also I think Nintendo was in a good position to switch to the hybrid. First of all the WiiU wasn't extremely powerful. So they were able to get affordable mobile tech that could match the power of the WiiU. Secondly they released mid-gen. So the mobile tech they could offer is not too much of a stepdown from PS4 and XB1. I can see that with release of PS5 Switch loses multiplats shared with that platform. It still could be the case that Switch by then has big enough a userbase for 3rd-parties to support it with exclusives though.

Sony cannot do this. Mid-gen would mean they wait until the time of PS4 is long over. They have to release earlier. And then they could be in trouble creating a handheld that wields more power than the PS4.

The other possibility could be a hybrid alongside the PS5. But the same problem I see coming for the Switch: while at the moment multiplats are possible (see Doom), it will probably be impossible with the PS5 power-level. So a PS4-level hybrid will not get the new games, it will not have the Nintendo-exclusives and probably will not get much Sony exclusives (like the Vita). Even if it is successful, it will nibble at the markets of the outgoing PS4 and the coming PS5. This scenario offers problems on every angle.

No I think Sony is better off differentiating themself from Nintendo hybrids by creating a really powerful machine, supporting VR. If they make it really powerful, even a mid-gen release of Switch 2 might not be able to bring enough power to catch multiplats shared with PS5. Nintendo in that case has more to bank on their exclusives and might actually be in a much more difficult situation. While Sony offfers the 'WOW'-tech.

It's true that Sony is more successful in europe. But that is because of better marketing, better brand value. Microsoft could build that, although it will take time and resources. Japan is another matter, they seemingly prefer japanese companies.

For the digital stuff: I'm not even sure your PS4-purchases will work on PS5. If not it doesn't matter. If it does - well BC never had much impact, that's why most companies neglected it. We talk about old games. People will look out for the new games. Sure, BC is nice, but it will not decide the console race.

I agree that the games are most important. And Sony has goodfirst party and good connection to 3rd-parties. For MS to compete they must grow in this department.

And the power difference: I think you underestimate the gap between mobile tech and home console tech. Switch has the advantage to release mid-gen. That makes the difference look smaller. But if a hybrid and a home console are released alongside each other I expect to see the difference more clearly.

It's not just Europe tho, anywhere you go from the middle east to south east asia PS is king. MS has had more than enough time to build things, both brand value and 1st party, it's been 16 years since they entered, actually longer than Sega was in the game. If they haven't until now, they never will.

I think PS4 BC is a given due to the architecture, it's not needed to make the PS5 win the race but it'd be a minimal effort to enable.

I dont expect the PS5 Portable to release alongside the PS5, more like a mid gen launch.

I would love to see a PSP2, I have lots of fond memories of the original. The Vita was less amazing to me, as it didn't get all the great first party games. Unfortunately, Sony doesn't have the resources to develop a robust line-up for both a portable and a home console, I think (same problem Nintendo always had). So it's probably not a thing.

I can see it coming because that will be our future. As Turkish suggested. There could be other system. A dedicated and a hybrid. A normal PS5 and a Hybrid. 
I will not see any problem if both runs on the same architecture. One is just more powerful.  The ability to play Uncharted,  Horizon, God of War and Last of Us at home and outside. As for that 2-3 years from now do you think there won't be a stronger processor and Smaller but powerful rams?

Dedicated Console will died out in the future. Its best if they do it with PS5 or if they want to experiment then they could do it with PS4P first. 
They can be still different even if their console is a Hybrid. What if they integrated a tablet feature in their hybrid where it can play the games on Android devices.