It really depends on what I am making. If it's just a tablerunner, wall quilt, child's quilt or other item that I don't expect to last more than ten years, I will sometimes use different fabrics. If I am making an heirloom project, especially if it's hand-quilted, I only use good-quality cottons.
Yes, our pioneer ancestors did make quilts out of different things, but the ones that survived are the "special" quilts that were seldom actually used.