It's all part of the NFL is over-exposed issue. Probably Thursday Night Football is the straw that broke the camel's back, and sent MNF heading south. Now you had TWO nighttime games. So the "special prime time" timing of MNF was no longer special.
But for me what made Monday Night Football so special were the special announcers and their knowledge and interplay. Now the announcers are jags, and there's no discernible difference between a Monday night game and any other game.....other than the day and time.
And yes, for those of us on the East Coast, and who are not late night people, it can be tough staying up until Midnight just to watch a football game.