"mustaine WAS on an ego trip'? he has always been on an ego trip since his days with the fledgling metallica. the guy is a perfectionist when it comes to his music- he appears to be very passionate about it to the point of being overly obsessive. i am a BIG megadeth (mustaine) fan, but the dude can be a real jerk at times.
he is in good company however when it comes to musicians being jerks- yngwie malmsteen is the same way- and then there is that guy from guns and roses that personifies the word JERK.
I think at that time Mustaine was on a big ego trip and noone could please him. If I remember right that's how it was. I'm not a metal head anymore, but back in the day that's how I remember it.