Amateurs are amateurs, but have you tried to do an intensity block in training and have your base crumble a bit as a result? Here's a highly scientific illustration of what occurs:
For Pog, the first two weeks of the tour amounted to just that - I mean he was full on with the limited base he had. In my opinion he may also have enhanced his capacities by having his blood bag after the 5th stage beating. That way he remained competitive and even attacked to gain time, yes, but the flipside is that it allowed him to overdraft his bank accout even more, which made the eventual crash all the more spectacular.
Additionally, I think extinction has it right: following the current version of Vingo is, shall we say, fairly demanding in its own right.
Of course, other explanations are also possible. But the lack of base definitely contributed. His climbing level this year was better than last year. But his implosion, too, was worse.