I don't usually listen to songs that are ten or more minutes long. I think songs usually say everything in five minutes, tops. There are plenty of exceptions but I think there is a big difference between Wilco's "Less Than You Think" and Television's "Marquee Moon".
In the case of Wilco's "Less Than You Think," there is a sound collage of low hums that comes in after few minutes and it never lets up after fifteen minutes. There is no payoff for the time you spend waiting for something to happen. There is no big ending a la the Beatles' "A Day in the Life" (not that all long songs need one), but I after a few minutes of constant humming and buzzing, I just think, "Why bother? I'll just skip to the next track."
In the case of Television's "Marquee Moon," if the song was anything shorter than eleven minutes, I would feel short-changed. If you've ever heard the song, you know the song just keeps building and building and it all leads to a climactic end. Yes, there are extended guitar solos but they aren't about stretching the song out. Every part of the song is strong and complimentary, so if the song was edited down to a standard, verse-chorus-verse-bridge-chorus, I would want more.
Here's a curveball: Jimmy Eat World's "Goodbye Sky Harbor," the sixteen-minute track that ends Clarity. The song's outro essentially begins a couple of minutes into it and it just keeps going. Layers of guitars, backing vocals, keyboards, bells and electronic effects fade in and fade out, but the song kind of enters a trance. I think the whole outro is cool but I really like how the band plays the song live: they revert to the main riff but with distortion and end it at the five-minute mark.
My point is that most songs need to be done in a managable time. Sometimes artists are testing their listeners' patience by going on for well past the enjoyable mark. I don't mean to pick on Wilco here: the same album that contains "Less Than You Think" (A Ghost is Born) also has "Spiders (Kidsmoke)," an incredible ten-minute, Krautrock-meets-Television rocker. All I'm saying is this: some songs work as epics and some just don't at epic length.