Every single GT winner ever has benefited from luck in some way shape or form. Froome dominated both his Tour wins, and he still got lucky in a couple of things - Movistar and Saxo falling asleep at the wheel in stage 9 in 2013 after isolating him, and getting away with the illegal feed, for example - and Wiggins too - he got a parcours designed almost specifically for him and Contador didn't get banned until early in 2012 anyway. As for 2011, you have the issue of stage 1 where Contador and Samu's group got involved in a crash outside 3k to go, then Schleck got involved in a crash inside 3k to go which blocked the road, meaning they didn't get penalized time but it increased the time lost by Contador and Samu. 2008 and 2011 Vueltas have time bonuses to thank. 2009 Vuelta Valverde was lucky to even be on the road. Even many of Armstrong's wins included elements of luck - 2003, for example, when no matter how great his save through the cornfield was, he profited from newly laid tarmac putting paid to the strongest Beloki we ever saw, Zülle being caught up in the Passage du Gois in 1999, and so on. No matter who won in 2006 they would be lucky. Contador in 2007 of course got Rasmussen being pulled out the race in his favour. Ryder Hesjedal got the conservatism of the other favourites in his favour, and the 2013 Giro (like many other races) saw a key stage get annulled (see also the 1991 Vuelta where Mauri was struggling in the Catalan mountains in the cold before the Beret stage was cancelled, by the time they got to the Asturian climbs he was back in his comfort zone). 2004 Giro saw the worst parcours ever plus the Falzès mugging and the weakness of the field gave us Cunego as a GT winner, while the almighty 2010 Giro had a major factor being Pellizotti's biopassport case meaning Nibali was subbed in at the eleventh hour so, not quite at peak form, he was set to domestique for Basso rather than being co-leaders. 2012 Vuelta again, Contador was lucky they did the backdating version of the ban so that he was able to be there, although simultaneously that meant losing other races which creates obvious lucky wins for Schleck and Scarponi as a result. Quintana had the Stelvio stage with the complete confusion and the other riders stopping for a coffee and clean clothes and then not taking the gap seriously until it was too late. Savoldelli had di Luca cramping up at the base of Sestriere which prevented the continued cohesive work of him and Simoni. Menchov was lucky to get his 2005 Vuelta after capitulating in the Pajáres mugging, Heras was lucky to get it back after testing positive.
Literally any GT you can name, you can point to somewhere where the winner benefited from luck.