Someone pointed out in a thread somewhat recently that vintage quilts, being hand quilted, only have the thread running on one side of each stitch whereas machine quilted quilts will have thread on both sides of each stitch which would add to the stiffness. That seemed to ring really true to me, since it seems no matter how densely you hand quilt something, it still is softer than if you machine quilted it. Yes, different battings will make the quilt feel different too.