I don't think it's possible to paint everyone with the same brush, there is a large proportion of people that are absolutely motivated by money. For some it is necessity, others it's desire and/or greed. You're right that some people don't need money for motivation, but using cavemen as an example isn't proving much. Back then it was survival of the fittest, and if someone else had something you wanted/needed, you just fought for it or took it, exchanges of goods hadn't really kicked in. There are individuals who don't require money for motivation, but often it's because they already have the financial stability (at least without starving anyway) to be able to devote their time and energy to innovation.


And yes, there are other clear motivational aspects - glory is undoubtedly one, and not just for Olympians.