I understand the motivation behind this discipline; create some space every day to write and you will find that your writing improves. However, as is ably pointed out in the comments, this advice overlooks the pressures on modern working academics to teach ever-larger classes; their ‘service’; and as I’ve found observing my wife who’s a full time academic, an ever-increasing avalance of self-criticism, quality-framework reporting, and administrative miscellany (the one area you’d think that a university could employ clerical specialists to do). As a part-time PhD, of course I personal also have the burden of an actual job that occupies four days a week. There is also a difference between prolific and influential.
Daily writing is the best way to ensure consistent and amazing productivity.