Great discussion - a few random thoughts -
The time limits of the media available has always 'limited' the time music has on each 'disc' in the past, but now that is much less of an issue - given the ease of access to DVD writers in home computers perhaps we will see more really long releases (rather than 'this disc has every track by Black sabbath on it'), but apart from joining two Cds worth of my own music that were connected I must admit I have not considered it. I think it would take some time to work out what I would do for that length of time.
Also, remember that the 3 minute pop song was very specifically put together, I can recall hearing years ago about the reasons, but can only recall vaguely it was to do with general attention spans, creating variety to keep people hooked and it's easier to fit it in than an opera or whole symphony....more likely to make a lot of money that way.
As to time and effort for listening etc I think there are a huge variety of pressures and things affecting each of us. I know I grew up with LP's and just twenty or so minutes a side - so on first encounter of an hour long piece I was ecstatic - but I recognise that I too struggle with listening to 76 minutes unless it is part of something I am doing (or for Floating which was partly made that long so it lasted longer than a 'therapy' session and so did not disturb the client by stopping before they had finished). When I was younger I was able to spend hours just listening to music - even with a full time job. But now I have other responsibilities and it is not so easy. I also spend a lot of time listening to my own music, especially during the processes of creation so I do not listen as much to other people's music as I would like to do.
I wonder whether the actual instruments also 'limit' us. I know many guitarists who almost always have a guitar in their hands and are just 'playing' exploring sound and looking for the song that's waiting to arrive with them - but I have to turn everything on, check the connections etc - so it's not just about the time we listen, but how and why.
Oophoi said that the shorter penumbra releases he put out did not sell as well as he thought the quality of the music deserved - and he did get a number of comments/criticisms about there not being 70 minutes music on the discs.
Immersions comments about time and a meditative space have some truth in them, non western cultures do look at time and consciousness differently and it is rare to find people involved in anything like the Dine (or Navajo) Yeibichei ceremonies which can last for four days and nights with very specific (ie not made up as you go along) chants, music and actions. I am not suggesting that people try to take part in the Dine ceremonies but pointing out that they are a very different space to a concert or a festival as they engage every thread of the social/cultural/spiritual/survival weave of the tribe or people. i think that would make for very different listening.
Hey Mike, perhaps the next Hypnos release could be a collection of 3 minute tracks - each of us taking one of our albums and distilling it down to a 3 minute shot