In my own network and in my current role, I see people that should have left years ago, but they never got the hint that their careers stalled. I would have a direct conversation with my manager to see where the growth is and then verify that with action (Are they promoting other people instead of me? If yes, leave.).

As far as reaching staff and then jumping ship, I have no idea. I started my career 10 years ago and at the time, I thought "senior" was the highest option, but then staff role got created.

I wonder if in 10+ years, the IC ladder will get taller, so people don't feel "trapped" at staff level.

Title inflation is a thing even with ladders. I know of some non-tech industries where there are 15 levels to climb and at level 7 you were considered a director already.