Overtime is different than a raise. When you get a $20K bump in pay you do move into a new tax bracket, or at least most people would. OT is entirely different and not what you were referring to in your original analogy. OT is also not taxed at 75%, which is the number you mentioned as fair and reasonable. Even still, if your time and a half was being taxed at 75% I would recommend working at the normal rate instead. $10 normal rate > $3.75 OT rate after 75% taken out for taxes. (Your rate, not mine.)
You also overlook the fact that while businesses are posting record gains it is not just the top executives there that reap those rewards. Everyone who owns stock or has a pension benefits as well.