This whole 'high def textures' is such a joke... the phrase already knocks me out.
Think about it, what is the bottleneck with textures in a console game? Available RAM! Just because you can store more stuff on the disc, it does not mean that you can render a scene with noticeable visual differences. To be honest, PS3 may even have a little less space for textures because of how the Xenos framebuffer works with tiling...
The argument Laa-Yosh isn't that the PS3 can render more textures in a given pass than the XBOX-360, but that the disk can store more textures, and that future games may have so much content that they exceed DVD capacity. This means XBOX360 games will be forced to either go multi-disc or DVD-18, or they will have to ship with less game content if they want equal visual quality (because to fit more episodes and more missions, they may need to cut down on unique textures, or reduce texture resolution)
The XBOX360 has 8 times the RAM capacity of the XBOX1, and the PS3 has 16x the capacity of the PS2. As I have shown, compression doesn't change this much, thus on this basis alone, we can expect 8x to 16x the storage required for art assets compared to the previous generation game if games scale texture resolution to max out RAM. That means if a PS2 game took up 2GB of a DVD, it's going to take up 16 to 32gb if all of that data were textures. Even if you want to argue they'll only use half their RAM for textures, it's still a 4x multiplier which essentially means DVD-9 ain't big enough.
Moreover, just like Hollywood blockbuster movies, the game industry is getting bigger and bigger budgets and plowing more and more content into games. So while the actual instantaneous texture usage for a given scene may not exceeed RAM, the size of the levels and the number of episodes of the game might be far larger.
Finally, for some classes of games, like driving/flying sims, and RPGs, which feature huge draw distances and levels, but very predictable movement velocity, a streaming approach can allow you to exceed RAM usage using an LOD system, in that, one will have more textures than can fit in RAM (on disc) at highest LOD levels, but one doesn't have to load all of the LOD levels for every visible texture. And, making this work good is going to require either lots of HD space, or data duplication on optical media to reduce latency.
No matter how you slice it, the PS3 has an advantage of storage for game designers, and history has proven that when people said "you never need more than X amount of storage" and "you'll never use all of this", they have been shown to be wrong, most of the time surprisingly faster than thought.
