At the risk of sounding Nostalgic, the atmosphere at Maine Road was in decline from the minute they built the new Kippax. The atmosphere at the Brittania is crap compared to the Victoria Ground, The atmosphere at the Emerates is shocking compared to Highbury, The atmosphere at the Riverside is not what Ayresome Park was, The atmosphere at St Marys is nothing like what the Dell was nor The King Power anything like Filbert Street. The elimination of standing (lets look to the swamp pre / post where the club are at the same ground to see this) has reduced the atmosphere in almost every case (Villa Park, Stamford Bridge other cases in point).
One of the few grounds that has maintained any semblance of atmosphere is Goodison.
I have a feeling that most of us grumbling about atmosphere in grounds are of an age at least approaching our 50's, and that what we get now is what football will be for the foreseeable future. I don't see standing coming back, I don't see the end of corporate days out or tourism, nor do I see clubs (such as Everton) deciding to remain as they are and not rebuild old grounds or build new ones.
With core support watered down with apathetic tourists and corporates (everywhere) football is becoming like going to the theatre.... Enjoy the show on the pitch, and give some applause at the end....