Now that I'm done pressing the report button (which may be the very first time I did that for rude behaviour since the reputation system was abolished), let's attempt to get the level of discussion back up a little.
The kind of performance you need from any device depends on the ambition of the game that is going to run on it. Sure enough, the NGP isn't likely to struggle with Angry Birds, but yet when I'm looking at the PSP version of Angry Birds, that game struggles with performance. Why? One major reason seems to be that Angry Birds is a Mini, which runs on a higher level platform that also runs on PS3 (and Angry Birds doesn't run smoothly there either), making it less likely that the game was optimised to run on the PSP hardware. On the other hand, that suggests that Angry Birds would need to be heavily optimised to run on the PSP.
Now lets have a look at the NGP, where we're seeing various games that previously targetted only the HD consoles are now also being announced for NGP, and where developers have suggested that it is definitely possible to add NGP as a target for multi-platform development traditionally aimed only at the PS3, 360 and PC. The PhyreEngine 3 GDC presentation pointed out that the NGP can run the same kind of shaders, but they'll have to be simplified a bit. NGP can run the same models, but you may have to LOD more aggressively and/or strip some vertices and reduce textures. And the NGP still has less performance in the CPU area. The upside of the lower resolution of the NGP is that you need less memory, less vertices and textures to achieve a similar effect, and the image quality will still be high because the pixels are relatively smaller, even when factoring in the closer distance to your face. I already calculated back when the original PSP was launched that the pixel size of the original PSP was equivalent to many PC monitors when factoring in the distance, area of view covered, etc., and that still mostly holds up today, though much depends on how close you hold the screen to your face.
When designing the hardware, Sony has had to balance out price and performance, and do so taking into account day to day use. Contrary to some people's belief, the iPhone is primarily used for 2D graphics. Higher resolution therefore comes at a relatively small performance cost. When designing the NGP, Sony specifically wanted developers to be able to leverage their HD assets on a mobile platform. For demanding 3D graphics, every bit of resolution countes, witness even many HD games not running at 'native' resolutions. Also, the NGP has to be affordable to be able to reach a larger audience quick enough, which is another reason why a higher resolution screen could be prohibitive.
All of this suggests however that there is every reason to suggest that if the NGP is to run games similar to its non-portable HD brethren, you need to push the hardware. This is no different then how the PSP had to be pushed to be able to run PS2 hardware.