People are resistant to change - like inertia - but if pushed enough, they will. Burger King & Wendy's only went up 55% whereas McD went up twice that at +100%. McD could have kept their prices flat and gained business from them, remaining within their brand as the "cheap fast-food" option, but instead they seem poised to lose it? Well, I guess we will see.

Yeah, it is scary to see just how evil they - b/c with profits like you showed, they did not have to increase them all, so the fact that they not only did but did by that much is somewhat shocking.