They may not be obviously wrong, but the important point is that it remains a pure metaphysical speculation and that other metaphysical systems exist, and other people even deny that any metaphysical system can ever be "true" (or real or whatever). The last point is rather consensual among modern philosophers: it is commonly assumed that any attempt to build a definitive metaphysical system will necessarily be a failure (because there is no definitive ground on which any concept rests). As a consequence, we have to rely on pragmatism (as you did in a previous comment). But anyway, the important point is that different approaches exist, and none is a definitive answer.