Barring crashes or other things that would ruin it, I expect this race will be decided by one of Roglic and Evenepoel breaking the other in one of the big mountain stages and taking, say, two minutes in the process. As good as Evenepoel was last Vuelta, he didn't have to face this magnitude of climbing, whereas Roglic destroyed everyone on the way to Covadonga the last time he got to do a big GT mountain stage in perfect health. In fact, I think Evenepoel's Vuelta-winning climbing was less impressive than Roglic' climbing in the 2019 and 2021 Vueltas, as well as the 2020 Tour. Moreover, I don't think Roglic has declined much, if at all, compared to that (rather it's Pogacar and Vingegaard who have improved).
So if anything, Evenepoel needs to break new ground to be the one to break the other rather than the other way round - ground that he didn't break in Catalunya. Now Catalunya definitely isn't a perfect predictor and Evenepoel still has room to grow in terms of his climbing, but as someone who voted for Evenepoel ahead of last year's Vuelta, I still have a bit more faith in Roglic for now when push comes to shove in the Alps.
As for third place, Thomas theoretically has a couple of minutes in hand on most of the other riders after the main TT, and that will be enough if he's around his level in last year's Tour. The problem is that his trackrecord suggests a 50/50 chance of a crash destroying his chances before we get there, he's at a point that age should be taking a toll on his climbing, and Hart seems likely to surpass him in the hierarchy the moment he struggles. Ultimately I do expect the latter to happen. Vlasov has had a disappointing spring and generally isn't that great in a GT, Ciccone will have some great days (if Covid doesn't derail him) but is ultimately a bit too inconsistent and not exactly a great time-trialist, which (barring a Caruso-type surprise - Vine seems a decent shout) leaves a battle between Hart and Almeida. I'm a bit worried that Hart is coming into form a little too quickly, so I'll go for Almeida resuming his role from Tirreno and Catalunya as best of the rest.