Where did I assert 3D was unnecessary? I believe I mentioned Deus Ex stunned me, and I would now add to that System Shock. To my mind, 3D is a logical evolution in gaming provided the game utilises all dimensions in gameplay mechanics, not just visually. You will find many "next-gen" games fail here.
Half-Life 2 is a decent game (maxed out on mods) but mechanically it does not approach Fallout. RPGs are intrinsically much deeper experiences than FPSes, and although Deus Ex showed that hybridisation is possible (you can actually build a tank character that doesn't use guns), Fallout character builds far exceed it in complexity through an open-ended world and non-linear storyline.
And they can tantalise me all they want with physics and environmental effects such as soil erosion, I won't take the bait. Not until developers can demonstrate an evolution in mechanics proportionate to their realtime photorealism.
I believe the internet will ensure the success of indies, shrug. People will pay them for the games they want to play.