Interesting post! I am not particularly well informed on those issues, but it captured my imagination, so here's my two cents about it: as you note about neural interfacing, it is hardly 'new', inasmuch as it has been hovering in popular culture for a few decades now - but that might be precisely the point.
The pervasive (and cunning) mood of techno-utopianism that constitute the vulgate of the new global middle-class, is not about truly 'new' technologies. It is not about 'new ideas' that might challenge or transform anybody's worldview, the way genuine innovation or progress should. It is rather about the realisation of the future as it was imagined when we were younger, when post-modernism still had a promising ring to it.
The material realisation and availability for consumption of the sci-fi dreams of the 80s and 90s is its true purpose, and in that sense it is 'retro-futurist', it aspires to 'a future that might have been'. In the process this imaginary future is made to look just about within reach, as long as we continue to feed the start-up world (or 'disruption' businesses, or whatever the buzz-word is those days) with our trust, with our faith and hopes.

You may have hit on the real reason, or a substantial reason among a handful, why there's excitement now. To put it simply, it's the possible on the verge of becoming actual, although you put it better than that. Thanks for that.