Commenter Dave Walser makes a good point:
What Professor Brown and others fail to understand is any measures that would increase the pay of adjunct professors would only increase the imbalance in the job market. If it were easier for an English PhD to make a living, more of us would have gotten that degree rather than pursuing a different field. I know I would have rather spent my days in college reading and discussing quality (and usually interesting) literature rather than parsing the tax code. I suspect, even today, I'd rather spend my days discussing Hamlet than accelerated depreciation. In making my choice between English and accounting, I listened to the price signal sent by starting salaries and earning potential. Dilute that price signal and many more will opt for a career in the humanities -- which makes sense since the humanities is more intrinsically interesting as a field.
In other words, fixing the misery would only distribute the misery to PhDs who couldn't get jobs as adjuncts.