The tech tree is not about world history so much as about tech development. And techs in this context is whatever can be researched by

. Everything that would be done with

or

doesn't really belong there (as a tech). And I think the eras as they are take more inspiration from whatever culture group got there first - e.g. the Ancient Era is not about Europe at all, and after what would be World War II the tech tree is more about America. Medieval is a bit of an exception, but even then very important things from that era came from Europe (especially the University). Doing this in a more inclusive way would be difficult - you would have to imagine how you think this invention would have been made in a different culture region.
In this context it is very important IMO to keep the different "ways of production" separate:

is about producing something you know - very little creativity is necessary.

is about choosing one of many different possible paths with no objective way to say what is better.

is about finding out what works, where you can say that A is better than B in a way. Things don't obsolete because they fall out of fashion (well, they shouldn't), but because they are superseded by something new (a new way to handle the need, or a way to remove the need altogether). This is of course an idealized picture, but even in this game we cannot go for a "realistic" one (with billions of different resources, replacing the map grid with something continuous, etc.).