No fundamental reason. ggplot2 was released 4 years after matplotlib, and the Python ecosystem was already centered around the latter by the time it became obvi

No fundamental reason. ggplot2 was released 4 years after matplotlib, and the Python ecosystem was already centered around the latter by the time it became obvious that the grammar of graphics approach was superior. Python's surging popularity in the data analysis space is also pretty recent. But any approach to a ggplot2 equivalent either has to abandon the massive ecosystem around matplotlib, or build on top of it – and matplotlib's heavily state-based approach makes that difficult. Plotnine is attempting to do that, I hear it's pretty good.