SPOILERS






Remember, Amelia made it to the other planet and began colonizing. The logical conclusion then is that the the colonization effort worked future descendents of that planet intervened to save the current civilization on earth. Both Plan A and Plan B worked, but ONLY because Plan B worked for Amelia. Amelia would have knowledge of who Cooper was and that would be information used to tailor the tesseract to him specifically. I have no clue how they'd know to show him the bookshelf in his daughter's room though.

There's still the problem of who created the wormhole. It couldn't have been anyone from earth because they never would have survived without it, thus never evolving physically or technologically advancing far enough to perceive and interact in more than three dimensions. They would have died out.

I don't necessarily need an explanation of who put it there but I'd like one, especially given the general sense that everything else came at the hands of more highly evolved humans and the wormhole is just sort of left as an unsolved mystery to my remembrance.