BCI is a hard problem, and the risk to reward ratio for current generation tech is too high except for a few isolated cases: non-invasive, which is low-resolution, and disease remediation, which is basically a measure of last resort. Given the poor payoff, the technology isn't invested into.
If we can get out of the gravity well / steep energy slope that prevents us from reaching the pinnacle, we can maybe one day become capable of performing brain copies and uploads, which effectively achieves immortality. This would be the most impactful technology ever developed for humans, should we still be relevant at that point. There's a huge hill to climb in getting there, and it's unlikely we'll see it within our lifetimes, if ever.
AGI, if developed first, would probably see little need in co-opting messy and overly-complicated human machines.
And there's always the chance we destroy ourselves first.