This substitutes the challenge of inventing a warp drive with the challenge of inventing a limitless free energy machine. An antimatter fueled rocket can't keep

This substitutes the challenge of inventing a warp drive with the challenge of inventing a limitless free energy machine. An antimatter fueled rocket can't keep up with what "1G, indefinitely" demands. Not even beamed power propulsion driven by a Dyson swarm can do that. I like the Revelation Space universe, but its fictional Conjoiner drive and the near-light-speed Lighthugger spacecraft powered by it are no closer to realization than any of Star Trek's technobabble. The same goes for the forever-accelerating Bussard ramjet vessel of Tau Zero.