I was just reading over your list of complaints and one thing stands out to me. In reference the lights dimming each time the motor spins to agitate. I know you are going to find the plastic cam. Now I think maybe you should test the capacitor. It should read 45 microfarads + or - 10% so no higher than 49% or lower that 41%. It might be bad causing a big draw on power.
Just an after thought.
I agree with your last statement I believe things are built with planned obsolescence in mind!