I'm scared to think of the money it would take to actually outdo the 360 and PS3 in sheer hardware these days. Both of them lose large amounts of money on their hardware (before you go ape**** on me for this, bear in mind that Sony and the big M utilize a sales scheme which makes up for hardware losses with their software - and even then, Sony doesn't even make enough to break even, and I'm not certain of Microsoft's statistics either), and the games themselves often have budgets in the tens of millions of dollars (or if you're Bungie, hundreds of millions of dollars)... honestly, is it even worth it anymore? Graphics beyond what we have now are rapidly approaching near-photorealistic quality, and the difference is only going to get less and less noticable from there, yet cost ludicrous amounts of money more.
You know, I kinda miss the days where the biggest developments in games were actually gameplay-related.