I am therefore very sad to see a plague of "pay-for-paper" services [pdf] that allow students to buy essays written by "professionals." These services are extremely good at meeting "needs" (see Figure -- click to enlarge -- and be sure to read what they say on plagiarism), but they are also a total rip off... not just for society, but for students.
They are a rip off for the student because their quality -- despite the hand picked "testimonials" on the websites -- is often crap, meaning that the students are paying good money for bad grades (or good grades that are not detected as ghosted).
Bottom line: Essay mills might make some money for under-employed writers in developing countries, but they undermine education for students and society, just as bike theft gives jobs to thieves while undermining security for bike owners and society. Just say
* Read this defense from one essay mill: "students need help!" whereas this professor sees essay mills as a response to "rot" in higher education.