There's been debate surrounding the atmosphere at OT since the 90s. In fact, people on Red Issue Sanc have recently pointed out that there was complaints about the atmosphere in the mid to late 80s aswell. It is hardly a new phenomenon. At Old Trafford, there are three big issues but all link to a wider culture problem. Now, in theory, the ticket prices aren't that bad. £37 for any game compares favorably with most games on the continent (Germany aside from the big leagues) the main issue is that there too many season tickets which means that game by game fans are spread over the ground (making it difficult to sit with groups of mates). There's then the issue of all seater stadiums, there's generally 10,000 stood up for the big games and it does make a difference. I would also argue that we, as a society, have changed. There was more anger/passion in the "good old days" people were almost more politically switched on and perhaps that shows. The atmosphere definitely declined after the summer of 2005 when the Glazers took over.