I think George a lot of the old tool designs were classic examples of products that survived over an extended period by virtue of being a very good fit to all the requirements (not just technical, but also price and other 'soft' ones) of users over an extended period of time. Not only that, these were very demanding users operating in an environment where there was very little room to accommodate anything that didn't do the business.
What does happen is that with time requirements can change - for example most professionals use power tools these days.
The fact is though that the proven designs of old planes for example still stand up as very effective solutions for those wanting to hand work wood. Just about all that can (perhaps) be said is that there's scope for somewhat higher quality finishing and materials given the ability of today's gentleman punter to tolerate a higher price. Modern manufacturing and technical advances have to some extent made developments feasible too - but the fact is that the designs are still very closely based on the originals.
That it's often possible to realistically argue that a well set up oldie is still a very realistic alternative is a testament to the rightness of the original designs...