Is complacency explored in the novel?
One of the difficult portions of the text is the ending, in which we see a completely defeated Winston basically give in to the power of big brother, not just in practice but in his mind as well. He traces 2+2=5 on the table and accepts the fact that Big Brother has won. The acceptance of the evil of Big Brother is troubling to the reader.
Orwell also explores the apathy of the proles who appear to drown themselves in alcohol and petty pursuits as well as the members of the party that Winston works with who have given themselves over to the Party.
If by complacency you mean apathy, it might be.
Throughout the book you see people that have opportunities to do something to effect change, but they choose not to. Part of that is fear for their lives, and part of that might indeed be complacency, but in any case, nobody changes dramatically here...except for those that have died.
It's incorrect, I think, to assume that anyone is satisfied with their lot in life, but Orwell is also trying to say that people don't know any better.