The poll says ~140M would migrate to the US if they could. That’s very different from saying 140M people would show up at our doorstep if we opened borders. It also says that 1/6 of Americans would leave if they could. You are ignoring these important qualifiers.

Edit: it’s actually 158M who would migrate to the US if they could, and ~55M Americans who would leave, for a total net inflow of 103M, if everyone could magically teleport to a new country on a one time basis.