People who spent a lifetime using these things probably knew a thing or two about technique for a variety of that are impossible for us to rediscover without go

People who spent a lifetime using these things probably knew a thing or two about technique for a variety of that are impossible for us to rediscover without going all in reliving exclusive dependence on those tools for generations. How would this knowledge not spread? Imitating others isn't exactly something that was only discovered recently. Try to make a child not imitate... If there is tool similarity spread over wide distances, it just means that some of those techniques must have had a very compelling efficiency advantage over other approaches that would be served better by a different shape.