As much as we all want DMT to last so long, or to have that 2-4 hour experience, I think we can also tend to take for granted the short nature of the DMT experience. I've only smoked DIPT (the auditory one) once, and I took one hit, and the very immediate effects were unpleasant. Although the unpleasantness passed rather quickly, the experience was six hours long from taking one hit. If I were in a bad DMT experience for that duration, I would probably never want to go back.
"Science without religion is lame. Religion without science is blind" - Albert Einstein
"The Mighty One appears, the horizon shines. Atum appears on the smell of his censing, the Sunshine- god has risen in the sky, the Mansion of the pyramidion is in joy and all its inmates are assembled, a voice calls out within the shrine, shouting reverberates around the Netherworld." - Egyptian Book of the Dead
"Man fears time, but time fears the Pyramids" - 9th century Arab proverb