MSc is the most successful driver ever to have driven an F1 car. He holds all sorts of records.
For him to return to F1 (after retiring) and especially at his age, he sullying his good name by getting whipped by Rosberg. He was out qualified by around 1s today...thats embarrassing for somebody of his stature.
He isn't short of money. He has more money than he knows what to do with and with all the sponsorship deals and investments he already has, even without F1, he would still be earning more money than most mortals can earn in a lifetime.
There simply is no need to draw this out any longer. If anybody is going to win for Mercedes, it will be Rosberg, unless MSc gets lucky. On skill alone, MSc cannot compete against Rosberg. He was beaten in the championship last season by him and the same pattern is now beginning to repeat itself this year. In order to justify the beating he is taking, his team and him are having to come up with creative reasons.