Switch is still only like 1/5th or 1/6th the size of an XBox One S. It's just not gonna happen even with a fan, that's too small of an area to not overheat.

You have to probably consider too that probably a good 50-60%+ of the internal part of the Switch is also going to have to be that battery too.

If Switch is even 1/3 of an XBox One given the limitations of portable, that's pretty impressive from that POV. 

PS4-like graphics are impossible with an ARM CPU, it is just too slow. The GPU performance may be fine but both need to be good in order to get successful results. Porting games is impossible with such a weak CPU because the PS4 is already at its limit and you would need to rewrite the complete engine.

ARM and Tegra are chanceless against a weak AMD-APU like the one found in PS4 and X1.
http://www.notebookcheck.net/SoC-Shootout-x86-vs-ARM.99496.0.html

A comparison of August 2013? Couldn't you find some more outdated data?

Price is probably the single biggest factor in the success of a system like this.  You're going to have a hard time selling an underpowered system to hardcore gamers if it costs just as much as the top consoles.  Likewise, you're going to have a hard time convincing casuals to part with $350 for something they'll only use a few hours per month.  It's also harder for kids to work one out of mom and dad.  At $250, you bring the system within reach of a lot more people.  I think an absolutely maximum reasonable price in the US for something like this is $299.

Yeah, ease of development is also important for attracting third party games.  Third party games are important for moving systems.  Moving systems is important for attracting third party games.  And the cycle goes on and on.  

At the end of the day, price, power, software support, marketing, ease of development, and everything else go hand in hand.  

Aren't people forgetting something rather important? Now I'm not a tech expert, but the fact that the Switch doesn't have a disk drive frees up quite a bit of space, no? A cartridge is considerably smaller than a CD. Therefor its size can't be used as an argument as to why it can't be near the power of the PS4 or XBONE, at least not to a certain extent. It also uses more up-to-date technology than the original PS4 or XBONE. If those consoles were made today, with the same power, they'd be smaller too.

The Slim version is considerably smaller than the original XBONE. And isn't the PS4 more powerful than the XBOX One despite being smaller? Size isn't everything you know. :) Maybe Nintendo got a desperate deal out of Nvidea, we don't really know, do we? How many devices use their Tegra X2 chips? Maybe Nvidea wanted a foothold in the console market. You know, taking a gamble that Nintendo catches fire again? Maybe Nintendo was more ergonomic in its design than Sony and MS aswell. Microsoft's console especially just looks bulky and ugly. Doesn't seem like an efficient design to me. Not sure who designed it, but they didn't do a very good job if you ask me.

Yeah, that was a pre-release rumour. It died afterwards =)

Discs occupy a lof of horizontal space but do they also occupy a lot of vertical? How much volume difference between disc and cartridge? But you may be right and that means a lot of space saved (but the discussion isn't mostly on the thickness as is in the depth+lenght because that would be the maximum size of the SOC. The second part is that Tegra wouldn't be expected to be stronger than Jaguar+GPU and at the same time drain little battery (that would probably occupy a volume that the consoles don't need) at the same time having the screen (that will also use volume) and needing more cooling since you will hold on your hands (which should also require more power and volume) seems like a very hard deal to have a console much smaller than PS4Slim and more powerfull. But of course we could be wrong, it just doesn't seems likely.

So you're arguing that if say, the PS4 never had a disc drive, it could be made significantly smaller? Because it absolutely couldn't. When the PS4 was released, it had experts literally scratching their heads, wondering how on earth Sony crammed that much power and heat management into such a small box. Sony are absolute masters at minizing the size of their electronics. Even then, they used advancements made in the last 3 years to make the PS4 slim even smaller. Let's look at a teardown of that:

https://www.youtube.com/watch?v=1AXERz8sjuA

Now you're guessing that can be made 8-10 times smaller volume wise by removing a drive that takes up less than 1/8 of the internal volume of the PS4 slim? That just doen't make sense. But that's what you think Nitendo might be able to achieve. I highly doubt that.

For the record, I think there will be a high power mode and lower power mode (when not docked), similar to a laptop. Nintendo could also save space from the kind of harddrive they use. Nintendo's main focus these past 5 years has been to cram as much power into a small tablet as possible, at an affordable price. Sony's main concern will not have been the size of the console, unlike Nintendo. At least that's what I think.