Why not? All the consoles of the year 2001+ ( PS2, Gamecube, XBOX ) can, why cant a modern blender on modern computers?
( And the effect Im talking about mainly is the invisibility effect, like Stealth Cameo from Metal Gear, invisibility from Megaman X8 and Super Smash Bros. Melee, ect.) Where they look watey-ish 
1). Blender doesn’t use the GPU for rendering
2). Blender uses raytracing to achieve the effect, I doubt raytracing is even involved in the realtime shaders.
Thats to bad. It takes so long to render said effect as well. Its really to bad Blender cant get it working in real time.
In blener (ad other 3d apps) it’s the cpu that does the work, not the graphic card. The graphic card can generate the pictures fast, but they aren’t the same quality as the ones rendered by the cpu.
Also in games small details and such are often accomplished by textures, not by modelling.
Blender’s OpenGL treatment is slow, faulty, antiquated.
José is implementing the GLSL shaders in his GSoc but this doesn’t address some more fundamental problems.
There must be a reason for that, since good OpenGL use is vital for Blender. I read quite often that design decision made 10 years ago make the task of updating that part of Blender very difficult.
Let’s pray for the arrival of an OpenGL dev that’ll have the competence, dedication and toughness to undertake that immense task. Could this be José if he stays after the GSocs?
Blender’s game engine can handle reflections to some extent. Check http://blenderartists.org/forum/showthread.php?t=89903 for example.