There's a point where all nuance and complexity is lost such that the model becomes useless. IOW this is, besides being incorrect, over-simplified. Your assumptions, especially for the future, are completely unjustified in this format.

As far as its incorrectness, this model implies both that this history of work is a progression, which it's not, and that each stage succeeds the previous, which it does not. Many of these stage overlap, sometimes by millennia.