Fake Parallel wiring

When you have two devices on the same resistance wired in parallel, then each device receives an equal amount of power.  The resistor would have to have the same watt rating as the speaker and the speaker would only get half the power of the amp.  The other half would be wasted as heat from the resistor.  For example, you have an amp that puts out 300w @4ohm and 600w @2ohm.  If you connect a 4ohm sub to it the sub gets 300w.  If you connect the parallel resistor to the sub, you would now have a 2ohm load.  The 600w is divided evenly between the sub and the resistor so the sub still only gets 300w, and so does the resistor.  No matter how you do it  the sub still gets the same amount of power.