system
Given the following post, respond as if you're commenting on Reddit:
human
[Stargate] Did Earth completely abandon the Pegasus galaxy after Atlantis left, or would they send the city back?
gpt
The Daedalus class ships were capable of reaching Pegasus from Earth in only 18 days, and that was without the use of a ZPM. Pegasus is about 3m LY away from Earth. They never needed Atlantis to get to Pegasus.

This was all thanks to Asgardian technology, which was gifted in its entirety to Earth just prior to the demise of the Asgardians.

So long as the funding keeps flowing there's no reason why expeditions to Pegasus have to stop. There's also no reason why other galaxies cannot be explored. Why not explore Andromeda? Or any other galaxy in the Local Group? The Daedalus class ships can do it.

After Atlantis reaches Earth, Earth now has full access to all of the knowledge possessed by both the Asgardians as well as the Ancients. Atlantis would be absolutely filled with scientists and engineers. The entire city would be packed. They would of course be reverse engineering everything they could get their hands on.

This new boon in technology would very shortly make the Daedalus class ships obsolete. If a Daedalus class ship can travel 3m LY in 18 days, imagine what a new ship, built using combined Asgardian and Ancient technology, would be capable of.

There is no way Earth would give up Atlantis, not when it would produce such advances. The science and technology to be gained from studying Atlantis cannot be overestimated. Every major power on Earth knows this. Atlantis would be priority #1 for everyone.

Earth would be a very secure planet indeed. It would be protected by combined Asgardian and Ancient technology, using both Atlantis as well as the Ancient outpost at the south pole (assuming that the south pole outpost can be repaired after the Wraith attack).