I've grown Sarracenia quite well in pure peat or long fiber sphagnum, in mixes also including quartz sand, and the pure evil that is perlite . . .
Yeah, I've come to hate perlite too. No matter how hard I compress my mix the first big rainstorm brings all of the perlite to the surface.
Fred P, that makes me feel a little better. But wouldn't we be wanting carbon dioxide to reach the roots, not necessarily oxygen (obviously both are in air)?
To put it simply.... roots don't photosynthesize, so don't really require CO2. They metabolize, and thus benefit from having access to O2. Therefore, having a porous, aerated soil provides O2 for the roots and is beneficial for the plant.