Right now, the most visible bottleneck is real world robotic control.

I kinda hope that one stays around for a long time, because robots controlled by AI competent enough to guide those robots through every step in their production from mining raw materials to end-of-assemble acceptance testing, is one where tiny mistakes kill everyone.

Like, say you've got a sticky 0 key and accidentally ask for more burgers than there is carbon in Earth's biosphere and atmosphere combined: if the sufficiently-competent AI is a little too eager to obey and not quite willing enough to say "no" or listen when told to "stop", that's enough to kill everyone.

Trust me I know, I co-founded a robotics startup, and robotics is HARD. But now it's becoming a hardware problem, the software will sort itself out soon, it's not a bottle neck that will keep us safe for long.

Abou sycophancy, I sense that it's much lower now with Opus 5.5. Yesterday I had to argue my viewpoint for quite a bit before it relented, on an issue I'm pretty sure I'm broadly correct. It's becoming a better sparring partner that actually pushes back and raises counter-arguments.