It is the speculation that fires the mind. If you did not have the tool would you be looking for bones?
Actually, my motivation is curiosity as opposed to speculation. For me, it is a problem unsolved, an answer to the question, "Who made these?" to which the answer is, "Nobody knows." Speculation, although loads of fun, will only bring bias to the situation for me at this point. And that, might I add, is how we got here in the first place.
A group of scientists speculated that Native Americans were too primitive to do anything other than walk across a land bridge at the end of the Pleistocene, following big game. There was never any evidence that the Bering Land Bridge was the only way and oral traditions to the contrary were summarily ignored.
That's a great example of racial bias, isn't it. The Hopis' oral traditions talk about wandering through North and South America before finding their home. They even traveled to the Great White Wall in the north but it was forbidden to cross over ... that tradition is simply ignored.