They have no resources? We already know they rebuild the Mass relays which is impossible with "no resources". You keep acting like the Milky Way ended after the Reapers defeat. It didn't. The crucible alone catapulted the technology of the survivors. With Synthesis and Control the knowledge and technology of the Reapers is there to be studied and developed. We also know that Reapers can communicate over vast distances. Again the theory doesn't hold nor does your explanations.
Just because it was prepared to operate on its own with no extra help doesn't mean some can't be sent. Why are you honestly believing that no one at all increase FTL speed or any technology after the defeat of the Reapers? You honestly believe that Krogans and Salarians would work together to cure the genophage? That a SR3 could be developed? Nothing you or others have stated leads any credibility to the Andromeda expedition being launched prior to, or during, the Reaper crisis.