I wrote this nice long post in response to Starboy, and it didn't get posted.
Let me try to sum it up I guess:
1.
Because of natural causes (plate techtonics, erosion, etc.) we have no idea how much of our past history has been destroyed and is now impossible for us to learn. Its possible (though probably unlikely), that the evidence of the dinosaur to bird transition has been lost in this way.
2.
Humans didn't just start evolving all over the world at the same time.
Some of the oldest hominid fossils found were in southern and western Africa. The Olduvai Gorge is where Australopithecus was found by the Leakey family. Hadar, Ethiopia is where the famous 'Lucy' skeleton was found.
If a human-ape missing link is going to be found, most likely it will be in Africa.
Now, that said, the dinosaur-bird missing link is most likely to be found in one area of the world. Indications would point to China, since so many discoveries have been made there already, but there is a lot of territory to search, and for a westerner to get into China for an expedition is NOT easy.
(I think there was some 70 years between the expedition by Roy Chapman Andrews and whoever went next.)