In talk of the Wii U, discussion of scalability was mentioned.  Idea is to come up with an engine that scales, so you can have it play down really low, or scale up real high.  This approach has been used to get games to work on a wide range of PCs.  Well, I am wondering how effective scalability is, as far as results in graphics, and so on, as compared to coding to specific specs.  On this note, I will go a bit off and date myselfsome here, and remember when PC games went from CGA to EGA, and got more colors.  I did notice, back in the day, when the games added EGA, that the graphics in CGA ended up looking markedly worse.  They just didn't look good.  Sure, you still got support but the effort wasn't put into the lower end and I tended to notice a lack of some artistic touches.  Also, some games just didn't perform as well, even if they could run.

So, anyone who knows about scalable engines, can you speak to this.  Is it generally better to code to set specs, or is it possible to do a scalable engine and get results that are about the same?  I am not sure, because I am pretty sure that you end up having early next gen titles not looking as good as they could, because resources like the render models, will often be set for current generation titles, so they don't have as much detail as they could.  Have they resolved all these issues?

It's better to have a certain limit. UE4 should be looking great, but because the scalability, the Samaritan Demo (UE3) does look better. I let you compare:
Samaritan Tech Demo: http://www.youtube.com/watch?v=RSXyztq_0uM
Elemental Tech Demo: http://www.youtube.com/watch?v=lY20pxEQM-A

Yes working with fixed specs will let you get the best out of the hardware.
Working with a fixed set in stone resolution saves a ton of trouble while coding and allows you to make it look as good as possible. Same for matching animation to a specific frame rate, matching textures and filtering techniques to a certain resolution, matching detail to a set draw distance and field of view, etc.
Hard coded constants are always more efficient then a scalable engine.

That doesn't mean a scalable engine can't produce almost as good results on consoles, since the engine will be compiled to that specific target. Hence no video options available on console. The same engine compiled for pc is a lot less efficient since it has to work with tons of different configurations.

It's always better to work with specific hardware/software specs from a development perspective. That's why most console games perform better than PC games, and why exclusives perform better than most multiplat games.

From a business perspective, scalability is necessary. Most people don't have high end PCs and most people aren't early console adopters, so developing a game engine that can adapt to multiple set ups is generally a smart approach.

And again to the Wii U here, which is part of my asking this.  I am not seeing signs that companies are going to bother working on games that would scale down to what the Wii U does, so I was curious here.  When it comes to scaling also, does a game have to be built with scaling in mind, or could companies later then decide to scale down an effort?   I know the likes of Civilization: Revolution was a total rewrite.