I don't like voodoo thing being overly attached to Nibali. Yes, it was funny in the beginning, but let's face it. Kruijswijk's crash in Giro 2016 is no voodoo, the guy tried to do something he wasn't comfortable with and he crashed, it was 100% his mistake. As much as you can break an opponent on a climb, you can do it on the descent too (just ask Zakarin). I don't exactly remember the Froome's crash in Tour 2014, but it was during one of the crucial stages in the bad weather, the one stage where you need to be alert all the time, ride at the front and be on the offensive. I do however agree that Contador's crash in the same Tour was a very big misfortune, but those kind of crashes became Contador's MO in his later Tours.
On the other side, Nibali himself had 3 voodoo moments in some of the crucial races of his career. He crashed on the wet road in Firenze 2013 WC, while on the offensive and going for gold, it wasn't given that he'd win it, but he managed to get 4th place injured in the end. The second crash was again on a decent, this time going for (almost certain) gold in Rio 2016 Olympics, in his probably once in a lifetime opportunity to became an Olympic champion. Those two crashes can be compared to the Kruijswijk and Froome crashes, both were his own fault. But the third was the bizarre one and the one I don't like voodoo being connected to him anymore. He was going exceptionally well in the Tour 2018, until a f* fan broke his vertebrae. By the looks of that Tour, I'm not so convinced Nibali wouldn't beat Geraint Thomas in a one v one fight in GT's 3rd week. The other two podium finishers were Froome and Dumoulin, both heavily tired after the brutal Giro.
That back injury also prevented him from being anywhere near competitive at the Worlds 2018 RR and probably even hindered his Giro 2019 campaign.