While it's obvious that everybody makes mistakes and has blind spots, I'd wager that, in general, being more knowledgeable gives you better tools to spot actual holes.

And sure, experts too can be narrow-minded and smug. Just like everybody else.

No they don't. That never happens. Would you expect someone who knows nothing about programming to identify flaws in a computer language?

Of course not. You expect it will be people who actually understand the field that can identify issues.