The point was that the quality and kind of the batteries mattered, Carbon/Zinc were vastly superior in the Game Gear to NiCd batteries even then, and Duracell has and had entry-level batteries pretty much on par with no-name batteries but not much better. The Game Gear needed the batteries to hold their voltage of 3.5V much more than the Game Boy did

I could see a PlayStation Switch, but it would have to be a successor to the Vita. I can't even imagine Sony trying to make a PS5 or PS6 as a hybrid. The power would be far too compromised.

A - PSP was announced in 2003. It didn't launch until March 2005. And it had no games, except for Lumines (was that a launch game?) and the terrible Ridge Racer port. Like you said in B, DS beat the PSP to market, however, it was in development since early 2003 and the rumors started at the end of 2003. I wouldn't say DS was rushed to market. And in the DSes first year it got some killer games:

Castlevania DS
Mario Kart DS
Meteos
Bomberman
Animal Crossing DS
Nintendogs

PSP may as well have been dead in the water...and it was by 2007 when the DS was still kicking ass and taking names.

C - The 3DS's problems were numerous. But again, the first party line-up wasn't that rushed in 2011. And Vita's problem was once again, no games.

D - Nintendo only pushed Motion Plus because no one was gonna buy another add-on for their Wii-motes. And by the time M+ came around, the sales of the Wii were stagnating. Believe it or not, at one point, the Wii had 49.9% market share.

The only way I could see a hybrid would indeed be a Vita successor, but with a PSNow subscription to stream PS5 games to it, as even by 2020 reaching PS4 GPU power in a handheld format is too much (XBO power should be feasible, but PS4, while doable, would be highly unpractical and drain the battery way too fast). But this comes with the problems mentioned before with bandwith, data caps, and the high costs of high data cap mobile services.

There is no way Sony can ignore the mobile market. If Sony thinks about recovering Japan, the new PSP is no brainer. Looking at the latest Sony patents for the Sony PS5 controller, Sony will offer the option of playing PS4 games and partially PS5 using a detachable screen. I think that the system will play all ps4 games nativly and stream newer PS5 games. Mobile PSP does not have to have the same computing power as PS4. Not every game must be displayed in 1080p. The 900p -720p is sufficient for mobile gaming, and there is a more cost-effective option when it comes to the battery. In addition, such a screen can be easily used for VR (switch the screen into the shell headset), lowering the price of the headset (PS VR is one creen devided).

In addition, assuming that the new dualshock will be able to be split into two separate controllers, it gives you a fast and cheap alternative to PS MOVE (a standard VR game controller). The only question is whether it is really possible and it will come into force or are only patents that will never be brought into production.

I agree to the theory, but the Vita shows what happened in practice.

Sony would need to support the handheld, and I fear after the Vita a lot got burned and don't expect Sony to give a handheld proper software support. Also, SD cards or M.2 sticks as HDD expansion instead of their own, proprietary in-house design. I'd love to be positively surprised here, though.

Neither Ninteno nor Sony have such opportunities to produce dedicated games for heanhelds and stationary consoles at the same time. Handhelds only make sense as an extension of entertainment from stationary consoles. I absolutely agree with you about sd cards. They must be ordinary cheap sd cards. This time it is not about selling cards and other stupid things, but about gathering as many users in Playstation  Universe as possible and transfer them to Playstation Services (Playstation now) as soon as 5G becomes real.

Hence Nintendos Hybrid console. But that's a move Sony can't do without leaving the high-end to Microsoft, so they won't do it.

This is probably the best response. DS would be the first console that they went with the compromise. I think the issue with the Wii U is that the value of the gamepad wasn’t seen as being very high; it was a test and misfire. Right from the get-go people considered the Wii U a half-baked concept (sometimes euphemized as a stop-gap console) - and I think Switch is what they wanted but A) Chipset tech wasn’t cheap enough, and B) Battery tech needed some advances (production wise, mainly).

So people weren’t sold on the compromise for the Wii U, and instead it came off as a slightly more powerful Wii for a lot more money, and a clunkier/slower interface which lacked the charm and sleek intuitive simplicity of the prior console.

Switch returned to the sleek simplicity, actually, more simplistic than the Wii since the array of Channels (voting, Mii Plaza, weather globe, news, etc...) are not present... although they DO have the My Nintendo channel, which is basically what the Switch game news channel is. I would love to see some more of that Wii charm brought back to life, but I don’t know the price of its maintenance.

3DS, launched with what I felt was a decent price tag; but its 3D was severely attacked by the media - particularly UK tabloids like The Sun and The Daily Mail - saying it could permanently damage vision, cause seizures, etc... Which severely damaged the image. Although 3DS wasn’t the greatest implementation either since it had a usability range - if you went off of it, the image on the screen would distort heavily (until new3DS).

Again, Switch came in with very solid tech, and a capacitive touch screen, instead of a resistive touch screen & stylus. It is the true successor to the Wii and DS. Throwing out all of the new features from the 3DS and Wii U - they were IMO failures, and didn’t fit the blue ocean model since they weren’t addressing an unserved desire in the marketplace (well, glasses free 3D WOULD have, but the tech implementation was bad).