um i dont know if you missed it but Orochimaru did what he set out to do

he killed the 3rd, that was the WHOLE reason for invasion.

so he did achieve something


Sasuke cannot go back now, there is no point in going back as he will just leave again, nothing has changed with Sasuke. even IF Naruto and crew deal with the sound nin, Kimimaro will show up and leave with Sasuke