Coming 4th in that field in 2009 (even without starting as team leader as he apparently did) will have surely given him at least the inkling that it would be possible to win it one day.
2010 was horrible, not least because no-one at Sky at the time was focussing on developing rider fitness, following the standard, at the time, dictum that that was the responsibility of the riders and Wiggins was going through one of his irresponsible phases.
2011 he was on the sort of form that would have probably seen him podium the Tour before he broke his collarbone, and 2012 was a year when everything came together and he even managed to ride through the same pot hole as Froome on that early stage while not suffering a puncture as his team mate did.
Prior to 2009 he had accepted that he would never achieve that particular childhood dream of winning the Tour, (from his book) and after that 4th place suddenly he had hope. We can argue all day about whether the change in his ambition was due to diet, belief and luck, or the rest of the peloton reducing their dependence on the doping for whatever reason, or Wiggins himself crossing to the dark side after all his history of outspokenness on the subject, In my opinion it is a combination of the first two, in many peoples in this forum it is the latter.
In 2009 he was still a domestique at heart, and had to be forcefully trained to actually live with the heads of state on a few stages at the Giro that year. He still seems to lack the killer instinct that makes him want to win races although I noticed some signs in Catalunya this year particularly with the descent attack that he is maybe finally learning this skill and in my opinion again he has never prior to this year learned to be comfortable against anything other than the clock. He only won the tour when his team managed to convert that feat into numbers for him and circumstances aligned so that it all worked out according to plan.
Yes it was a tour suited to him with 100km of TT.
Yes he had a team-mate strong enough to win it himself who eventually came 2nd by about three minutes over third place, and helped pace him over the last few km of the mountain stages.
None of that invalidates what he did, turning himself from a pure chrono man whether over 4km or 40km into an all rounder capable of winning a Tour in the right circumstances.
I think he genuinely was 'trying' to win the Tour in 2010, but without the necessary base fitness due to lack of training. In 2011 he had the fitness but probably had lost too much weight and would have only podiumed at best if he hadn't been injured in the crash. In 2012 at a couple of kilos heavier he had the resilience to make it through the (relatively easy) race with a strong team supporting him.
I know I'm only a Johnny come Lately fan of road racing but I can read and make my own mind up. I commend him for deciding to go for another challenge rather than following the Tour Only template of LA etc. His attempt at the Giro came to naught but he had always stated prior to the race that Nibali was the favourite on his home ground and no-one could have predicted the conditions being as bad as they were.
I want to see him going for some one day challenges next year and maybe the year after before switching to a track team pursuit/road TT attempt on Rio because that is where I think he'd be happiest. I think Cav was right, he's not a natural born winner, but I think he's done enough over the last 13 years to prove himself one of the most physically gifted cyclists of his generation. Although in competition in IP he didn't beat 4:15, before the virus 5 weeks pre-Beijing he was originally targetting 4:12 which is a different kettle of fish, power wise, and the evidence that that improvement was on the cards dates back to his 2007 blogs, notably during his outspoken period.
Oh, and Froome is not Merckx, I'm not even convinced yet he can take this TdF and am half expecting Saxo and Contador to take him to the cleaners which as a Sky fan is an uncomfortable feeling.