5+ years and 321 contributors later, I can state that Bokeh was not easy to write. Fairly sure MPL and Plotly devs would disagree with this assessment as well.

5+ years and 321 contributors later, I can state that Bokeh was not easy to write. Fairly sure MPL and Plotly devs would disagree with this assessment as well. Python has a multitude of vis systems because there are multiple use-cases, sometimes overlapping and sometimes not, and different people prioritize these very differently (and that's OK).