Alabama, FSU, Oregon, TCU, Baylor and Ohio State have 0 or 1 losses each. They make a readily apparent top six. Georgia Tech, Missouri, Wisconsin, Kansas State and Arizona could all be conference champions next week, but each of them have two losses so it doesn't help them any even if they win. It just removes their opponent from the playoff picture.
We can imagine a lot of bizarre scenarios where all 6 of the top 6 teams lose next week, but realistically that's just not going to happen. Assuming only 2 of the top 6 teams lose, the remaining 4 will slide in without a hitch and without any controversy. It's extremely unlikely for all 6 of the top 6 teams to win next week, as they're all going up against top competition. Next week will separate the wheat from the chaff and a top four will crystallize beyond all doubt.
Colorado State and Marshall losing cleared up the Group of 5 contenders. Boise State will be going to the New Year's Bowl without any serious complaints from anyone else.
The selection committee lucked out this time with Marshall losing in overtime to Western Kentucky, but they won't always be so lucky. Until the playoff is expanded to include every deserving team, menaces like undefeated Marshall will keep appearing in the future.