I was fine playing the n64 zeldas on a keyboard.... I think it's because companies wouldn't feel comfortable actually spending on developement costs for the DS.

¿Did you want the truth? Is Easy, because is cheaper use PSX graphics engines and tools than N64' ones, ¿Why? N64 tools never where cheap, and today either.

Well, if you ask me. Nintendo underestimated the analog control of the touch screen.

The original DS shipped with a wrist strap, and on it was a thumb stylus. When I played Super Mario 64 DS, I chose "Touch Mode" as the control option and controlled Mario by sliding the thumb stylus around the touch screen. The control was actually smooth and I can move Mario around without many hitches.

3D games can work by having all the action taking place at the top screen and use the touch screen to house a map/options/radar or whatever and let the player move the character using the thumb stylus. Given the number of people who have used laptops, it shouldn't be hard to learn.

However, when the DS lite was released, Nintendo actually dropped the thumb stylus from the packaging, thus most DS players are denied that control option!

You can better ask why not more N64 ports on the VC where I'd rather see them. N64 remakes on DS aren't really working. Besides aren't we getting tired of all those remakes on the DS already?

We can use the touch screen to simulate some buttons.

I don't see the need for a bunch of N64 ports on the DS. Especially considering most games will end up with gimped controls.

My primary issue with the PSP is that most of the games feel like downgraded ps2 games (like God of War: Chains of Olympus) with often gimped controls (particularly shooters like Resistance: Retribution).

What I want from my handhelds are more unique experiences like Prof. Layton, Scribblenauts, and Patapon. The DS gives me this in spades. I couldn't ask for much else.

What's the point if they can be ported over weekend for PSP and PS3 online store?

I dunno Square wants more money with a 40 dollar DS game? 

Could they be made? Probably. Are they being made? Not now, and probably not in the near future.

DS cards, despite looking vaguely similar to the untrained eye, are actually completely different technology from SD cards (for starters, DS cards use ROM chips instead of flash memory). You cannot use the capabilities of one to infer possible capabilities of the other.

As mentioned before the d-pad doesn't work too well with 3D games. The end boss battle with Bowser in Super Mario 64 DS was a pain.