Honestly 100k changes nothing. It's great that they sold so much in the first week and that they could well sell a good number over 100k overall and i'm happy to see them sell better than any single in over 8 years. But if that is enough for us then we'll be no better off than when we just accepted 40k overall sales as normal. Relish this moment and cherish it and there is no reason to get cocky over just this. Personally i want to cheer Morning Musume on to more and greater sales. I won't be satisfied with just 100k in one week i want to see a single that sells 250k in it's first week next.
There is no ceiling to what Morning Musume can achieve we know that from the past and there is no limit to what they can achieve again but if we as fans get comfortable with 40-50k sales overall then so will management and Morning Musume themselves. And i don't think anyone wants that.