I agree to an extent, but for Washington State they lost 5 of 6 games in a row which is why they've dropped. Also, no one expected them to be good in the preseason, where as Mississippi State was projected to be a top 10 team and preseason expectations can infiltrate rankings deep into conference play depending on schedules.
Washington State has a cushy schedule coming up aside from the Arizona game, as every other game left is against a team with a losing conference record. And they have 4 games lined up against the bottom feeders (Utah, Washington, and Cal) so they should finish with a solid record.