This is long over due. I did a presentation[1,2] at the research showcase more than a year ago (January 2016) that showed some fascinating productivity dynamics using content persistence measures. Well, I've finally taken the material and fleshed out the report on Meta.
Anonymous editors contribute substantially to overall productivity (15-25%); however, their proportion of overall contribution proportion has been steadily declining since the beginning of 2006
As Wikipedia declined in number of editors, efficiency increased at a rate that was proportional -- enough to maintain a nearly consistent overall level of productivity. This means that Wikipedia has been getting more efficient
Tools and bots don't explain the increase in overall efficiency, but tool-assisted productive contributions are certainly on the rise.