Quantum gravity is not a precursor to technology, so far as we know.
Quantum gravity was a replacement for something that used to be known as the unified field.
Einstein wasn't chasing quantum gravity; he was chasing unified field theory that fell out of favor.
Unified field theory becomes sort of like a joke old-timey expression for the future of physics, and we substituted quantum gravity for the merger of quantum theory, one field theory, quantum mechanics, and gravitational physics under general relativity.
The 1957 conference was a confluence of the two families: the Witten's and the DeWitt's with Feynman, Wheeler, and all of these unbelievable characters in attendance.
This pivotal strange experience that people are smoking the ganja on extending general relativity to places that it's never been extended, and the highbrow version of this doesn't work, and the lowbrow version of this doesn't work, so far as we know.
The lowbrow version is called pseudoscientific anti-gravity, gravity shielding, electrogravitics, gravity dynamics.
The highbrow version of this is called quantum gravity, and all the most respectable people are in it, and it just doesn't work.
The dog doesn't hunt, and anybody who questions it is a crackpot.
We have got to purge the physics community of its quackery, and the quackery is coming from the high Prestige version of this.
The high Prestige version of anti-gravity is called quantum gravity, and it just doesn't work.
They've crawled into the map prison built by Einstein, and they know that it's not right because there are these two singularities; there's this Singularity at the beginning of time which we call the big bang.