Is Thomas really blaming the weather and traffic? Has he ever heard of leaving early? Maybe watch the news or weather the night before? This was not a surprise storm. Everyone knew it was going to be terrible out, and anyone with any common sense knew that meant that it was going to take a ridiculously long time to get anywhere. So you plan ahead, leave early, and then you are all set.
And by complaining about this, he made it much worse, because he is just demonstrating that he just doesn't get it. It is not about "motivation", it is about taking responsibility and having a sense of pride. With the way things have been going, not only should they not be arriving late, they should be there early, trying to fix things. I guarantee you that is what Belichick has been doing, and he expects that from everyone else.
As for the overall question, no, I don't think this team is blowing up. But I do think Adalius Thomas' days are numbered.