Because an album of the same songs, without new arrangement, is exactly that. And we all think that's mostly boring. Therein lies the danger. That's probably why there's not been a DVD yet.
I completely disagree with this, on the grounds that SX is BY FAR better live than on the albums. It's seriously to the point where I can't even bring myself to listen to most of the studio-versions of the songs any more (aside from stuff from V that is, and only because each song seamlessly transitions to the next). Anything from DWOT or TIO I will more often than not listen to on the live album as opposed to the actual albums (unless of course the song has no live versions available, in which case I settle for the album version).
Why, you ask? Because it's so much more energetic live. They of course have the tendency to often play slightly faster than the studio version, which for many songs (say, Eyes of Medusa and Church of the Machine) gives them a bit more of an added *oomph* factor. After hearing those versions, the studio versions are practically unlistenable for me, just because they sound so dull and lifeless.
And then there's stuff like the Divine Wings title-track which has that added key portion immediately before the final segment, in addition to the clean-guitar portion and keys echoing the theme near the beginning being drawn out further so as to create a suspenseful effect, which is not present on the album. And Through the Looking Glass with the additional solos, not to mention the much more upbeat tempo in comparison, makes that song shine far better than the album. Even when it comes to the Odyssey, I actually sometimes prefer a certain video on Youtube of the full song to the studio version (and THAT'S seriously saying something).
Also, having seen SX myself back in March, I can honestly say that some songs from Iconoclast and Paradise Lost that I either was not too keen on or just downright disliked (ie. Eve of Seduction, Serpents Kiss, End of Innocence, Dehumanized, etc.) are about 10x better live for reasons similar to those I listed above.
Hence, it's almost like buying superior versions if anything, assuming that the mixing and mastering of the concert audio is well done, which unfotunately was not exactly the case for Live on the Edge of Forever (and yet STILL I prefer it to the albums most of the time).
Also:
Kenneth R. said:
SX isn't the kind of band to re-arrange
What do you call performing the orchestral segments of V with guitar and bass in place of them like On the Breath of Poseidon and The Death of Balance? That's rearranging, I believe. Hell, most of their really elaborate songs are rearranged for live performances, which is the main reason as to why I think they're better live.
Some of you may not agree with everything I've said here, but it's what I think.
Also, the concert where SX performs V in it's entirety with a full orchestra is the greatest concert in history. Period.