Sure, but it's easy to be humble when you're essentially an institution. In fact, it's better that way, because it appears honest. It's far harder for an unproven fund manager to admit making egregious mistakes without making his shareholders nervous. Buffett has 50 years of beating the market to soothe stakeholder concerns. Most other managers don't.
For what it's worth - he has been this transparent about mistakes since the very beginning of taking on Berkshire management in the late 1960s (when he was in his 30s) - He makes fairly prudent predictions and plans in each yearly shareholder letter, and is quite fairly critical of himself when those predictions do not pan out.
I suppose. But, see, for example, the recent Cloudflare issues. They were pretty transparent, but missed big on the "humble" part. I don't think there would have been anything but upside had they gone with a humble approach.
