I think the biggest case for a bearish attitude towards AGI is simply that we don't take advantage of the intelligence we already have. Look at our elected human leaders, for Pete's sake.

If we had access to AGI today, we'd just find novel and interesting ways to ignore it, enslave it, gimp it, and/or bias it.

What, your preference would be to just unleash it upon the world? I wish the average software engineer had any foundation whatsoever in humanities and philosophy before being allowed to make such decisions, but alas, we are doomed.