That is your "logic". Haha. :D

Sony started bundling PS2s with the Network Adapter in 2003 though.  And in 2004 it became standard with the Slim.  And actually, you could use any old modem with the older PS2s too, you still technically wouldn't need a "PS2 peripheral" to play FFXI on a PS2 fat, all the necessary hardware for them are non-specialized.  And that's actually a hardware feature Sony touted early on.

Speculation's all we have to go on right now, there's no actual evidence any DSi or DSiWare games use the upclock speeds or extra RAM in the DSi/XL.  They do use the camera and flash drive in some cases though, but both those could technically be done on the DS/Lite with the proper expansions.  Hell, DS even had a RAM expansion for the Opera Browser too, the only real possible issue is the higher clocked ARM9.  

PS2 slims are actually higher clocked than launch PS2s btw, and PSP-2000/3000/Go have double the RAM PSP-1000 did.  I guess we should separate these systems also, just to be on the safe side. ;)

Actually, that's yours since you are the one stipulating the criteria for the DS.  If not, then please tell me how those consoles do not meet the same requirements. 

1) I haven't heard of that.  PS2 slim does not have the network adapter, it has an ethernet port.

2) Wtf? How would an old modem give you the slot for HDD? FF XI requires the original Sony HDD which can't be installed on anything else than the network adapter. Which is a peripheral.

3) So where is the expansion? Camera, added ram and the faster processor?

4) 299 vs 300mhz. Ok, I'll give you that. :) That last line makes it sound that you think I would care if first and later PSP models would be separated. I don't care. They just aren't the same case as DS/DSi.

At the end of the day, it really should all go back to what the hardware maker says.  Nintendo, Sony and Microsoft all tell us what they consider each "platform" and what hardware exactly falls under each, that dictates what they do with these platforms and really should itself be good enough.

iQue has nearly identical hardware to N64 and runs the same (adapted) games... should we consider it an N64?  The Super Game Boy and Game Boy Player actually each housed GB/C hardware inside and literally played GB/C games, should they add to the GB total?  Are SMS and Game Gear the same platform, you can play each's games on either with the proper adapters?  There are tons of issues that come up when you start defining a "platform" by it's chips alone, there's really more that goes into it than just that.

You said that you would stop arguing, I don't see that happening... but:

GB/GBC should be separated, they are different machines.

I have no idea why you mentioned PS1.

PS2 had only couple of japanese games which required a peripheral to run those games. Peripheral =/= feature. Removed peripheral support =/= new console.

N64, no idea why you mentioned it.

PSP has only one game that you can't play on the newer model. DSiware has 307 games which you can't play with the older model.

All 360 games can be played with every 360. You might need to buy a peripheral to do that.

So you think that Kinect is a new platform? :P

So again, as I already asked, what distinction do you draw?  1 game or 307 games (which incidently you state distribution models don't count earlier for PSP)?  As for the 2 you don't understand why I listed, look below.

PS1 - Net Yaroze. Model SCPH-5552 could play Video CD's (some Japanese games made on it) while none of the other 34 models and revisions could.  The DTL-H model series.

N64 - iQue.

1) The Network Adapter is an ethernet adapter/modem. It's just Sony's terminology, they even call the internal PS2 slim iteration a "Network Connector" not an ethernet port.

And yeah, in 2003 Sony started bundling PS2s with the NA for $199, they called it the "combo pack".  There was a Twisted Metal Black bundle too that holiday iirc.  

2) Ack, I forgot they use the same internal bay!  Yeah, you'd have to use the NA or it wouldn't fit... though this doesn't really change anything, since FFXI (and other games) are 100% incompatible with PS2 slim, even with hacks/workarounds.  Which, by your definition here makes it a different platform.

3) A camera was released with Face Training, a RAM expansion with the Opera Browser, an even a flash interface (SD card) in the Play-yan.  Most 3rd party flash cards/adapters actually expand the DS' internal RAM too (for homebrew use, emulators, etc), the only possible issue is the upclocked ARM9, and currently we have no direct evidence of any game actually using it.

4) Actually, they are.  You can't use any PSN games on a PSP1000/2000/3000 without a MS/duo (which you seem hellbent on defining as a "peripheral" if the whole HDD argument above is any indication) while you can on a Go.   If DSi gets cracked, you'll be able to do the same on a DS/Lite.

There are other incompatibility issues with PS2 models due to hardware revisions.

HDD bay = feature =/= peripheral

Removed game support = new console?