If he doesn't crash it's almost 100%. We've seen how dominant he has been in Strade/Catalunya/LBL, there is no way that, so long as he doesn't crash, anyone on that Giro start list comes close to him
The only 2 riders who have a chance of staying close to him in the mountains are Vingegaard and Roglic. Just look at the last 2 years and how far ahead they were of the field. Vingegaard is injured and I can't see him winning it. Roglic is not in the best form this year, plus it seems unlikely he will drop Pogi even if he can outsprint him on a good day.
Evenepoel is overrated, may gain some time in the TTs but he will get dropped early on multiple mountain stages. I know he lost time to others on Granon and Loze but Granon was down largely to tactics (he still would have been dropped by Vingo but it must be tactics to Bardet and Quintana etc) and Loze was because he had poor prep and partly as knew he had lost. But every time Vingo and Pogi attacked they would just take a minute on the field in no time. Usual laws about he might have a bad day blah blah blah don't apply. All this 10% chance even if he stays upright then he still might lose doesn't apply to Pogi, certainly in the Giro field
The question is, how likely is he to crash? Now, crashes are frequent in cycling as we all know and so I reckon he is about 75% to win the double