I can't see a point in dragging it on in this direction or era either. While Covenant may be a fun movie it seems like the story will be clear-cut and I think doing a continued monster mash with the same creature in the same timeframe just diminishes the alien and the original film.
Granted, my preferred sequel to Prometheus would've had them leapfrogging the film timeline entirely and having Shaw and David awaken from cryo five hundred years later - making these stories the larger superstructure of the Alien films as opposed to slavish prequels - but that's moot and here we are.