Kimi,s persona has always been one of, so laid back he is almost asleep. He has never given a toss about any of the bullshit surrounding F1, but once in the car, there aren't many who are better than him. If he would rather be doing something else, he would. He,s very much his own man.
I agree that Hamilton hasn't been at the top of his game so far this season. The Ferrari is obviously the quicker car, but I don't think that's the whole story.
It could be that the current crap formula is getting him down. He is a master at "driving the wheels of the thing", but the current formula, with its emphasis on conserving fuel, tyres, engines, transmissions etc. etc. discourages that, which is why the whole thing needs scrapping and starting again from scratch.
I suspect he will either find away of getting back to his old self during the season, or make a shock retirement announcement at the end of the year.