> I reckon with the speed of generative AI, that lines up pretty well with when my usefulness will be roughly equal to 0.
Unless you are in a tight specialty area where the writing is on the wall, and you're already close to being replaceable, I think you're over-estimating things. We don't have the much-vaunted paperless office, we're still not really with it with driverless-cars, robots haven't replaced us all yet and we have more work rather than less: so much of what people thought was the future is really a bunch of stuff that isn't there yet, or is not going to actually happen.
I'm nearly 50, and what I've learned is that the more things change, the more they stay the same.
> It might be a bit late to start a new career path at that stage.
You can start whenever. There's a story of a woman, at 80, who said she wished she'd taken up violin at 60. "If I had, I could've been playing for 20 years".