I think steel shanks arent used because they would add some weight to the shoe and probably arent worth the trouble for an athletic shoe. Also with business shoes, you arent exactly running or jumping in them. With athletic shoes metal isnt used as it could possibly bend and be misshaped, which is somewhat hard to believe, but possible. I remember reading about the Jordan XX2s, and how originally it was going to use a titanium shank. Oddly enough during wear testing, they would find the shank to actually be bent out of its original shape, so they instead used a titanium coated plastic shank. With high grade TPU, you can control the durometer and what not, and yes it might bend a little, but it will return to its shape and well its cheaper which in the end is what matters to the big companies. Also the retail Lunar Vapor 8s do use a legitimate carbon fiber shank even though the matte finish makes it seem otherwise, but the same carbon fiber appears on the Kobe VIs. Also Fed did have shanks on his shoes at Dubai.
But yeah I def agree with you corners, on the sense that I too would like to see shoes that are more flat at the bottom like the Courtballistec 2.3s. I tend to find the shoe more stable.
Thanks for the pics FabFed!