Sure, Pinot has had a lot of bad luck. But you can't help but get the feeling that when it happens time and time again, it's not just bad luck. Theoretically speaking, the more "bad luck" you have, the less likely is it that it's just bad luck.
All riders crash from time to time - you can't avoid that, and you can call that bad luck. But it's very different how the riders react to those crashes and injuries. Physically, some simply recover better than others, and I think that Pinot simply just doesn't recover very well from injuries. Nothing wrong with that, that's just his body works. Regarding his psyche, I don't think he's mentally weak per se. He has bounced back from setbacks often enough that I don't think that's the case. But he does seem very erratic in that regard - I'm not sure how to put it in English, but he seems very "swingy" mentally.
He's a great rider and he could win a lot of big races, because when he's on top of his game, there are very few riders able to match him. I just don't think that succes will come in Grand Tours - except for stage wins.