Now that this has sunk in, I did think there was something strange about his body language, facial expression and general demeanour on the podium last week. I've just re-watched it and in hindsight it's there, plain as day, he's finished. He's done. He wasn't celebrating much and he seemed more relieved than he was happy. This is also why he gave a long rambling answer as to whether or not he would use #1 or #6 - he knew fine well he wasn't going to be here anyway.
I do relate to this as I have a similar mental attitute to challenges and undertakings. On sim racers for example, when I have won the championship on a particular game I won't go back to it. I rarely re-read books. I don't see the point in competing to complete, which is what he would be doing if he went back. He knows he's not going to win it again and racing for a few more years proves nothing.
He has made the correct decision. He has achieved something great and it is not going to be sullied by a dip in form. He draws a line under it, and moves on to something else.
Adios!
If I were Merc I'd be on the phone to Paul di Resta before just chucking Pascal in that car, but that's just me.