I think Carapaz should be the favorite probably yes. But I agree with Red Rick that the margin by which he is made favorite by the bookies is way too high. There are other contenders that have shown the same climbing ability as Carapaz in the past in my opinion.
I think the odds are not only about potential (climbing) ability, but also about trust in a rider being able to win
Yates has won the Vuelta in 2018, but since then, and even in the Giro 2018, he has been very inconsistent during GTs with at least one off-day. So with that in mind, it's clear that people may not expect him to win another GT.
Almeida has shown extreme improvements in last years' Giro and he has been consistently good in the last two years. But there's still a lot of uncertainty about his potential in GTs. Can he reach his climbing form from last year again? Additionally, last year he had nothing to lose after losing a lot of time early in the race, while the other GC guys didn't really have to consider him a threat for the podium anymore. This year everyone will chase him from the beginning.
López has podiumed the Vuelta and Giro, but he was never really close to winning them. He is clearly one of the best climbers when he is at his best (and IMO a better climber than Carapaz), but he also has the tendency to lose way too much time in ITTs, hilly finishes, bad weather, crashes etc. We can add to that that he's probably not the greatest at dealing with a lot of pressure or with setbacks. All that makes it rather unlikely for him to be a GT-winning rider. Do I think that he may win another big mountain stage in this Giro? Hell yeah. Do I believe that he'll ever win a GT? Hell no.
Landa is also a great climber, at times better than Carapaz. But even more than López, he is ill-fated in most of his GTs. He somehow always finds a way to lose a race or even get out of contention early on. Moreover, Landa has never even won a World Tour stage race in his whole career. So it's kind of hard to see him as a Giro winner now.
Of course, anything can happen and any of these guys has the potential to beat Carapaz. But the thing is that all these riders for some reason appear not to be too likely to win the race. While, in contrast, Carapaz has podiumed his last 3 GTs where he made an GC attempt, won the Giro already and also won the Olympic Road Race last year. He may not have as much potential as the others, but he is a winning guy.