Who needs to train before a race anyway can just use the 5500m total climbing stage the day before as climbing if only people had thought of that earlier who needs recovery anyway.
Of course he trains, but then he rides around Italy doing sod all outside time trials for 16 two and a half weeks. He knows that his whole race is two stages. The day before he gets in the break to test his legs, but doesn't overdo it. And then fresh as a daisy, a double World TT champion drops knackered GC riders.
Again your suspicion is down to your limited understanding of the sport