Yes, this is correct (on conservation of expected evidence, if nothing else: if experts were all convinced, then we'd believe the argument more).

Now, there's a whole host of reasons to suspect that the experts are not being rational with the AI risk argument (and if we didn't have those reasons, we'd be even more worried!), but the failure to convince experts is a (small) worry. Especially so with experts who have really grappled with the arguments and still reject them (though I can only think of one person in that category: Robin Hanson).