It does devalue the degree, and it does impose costs on those who don't cheat, by making it harder for them to establish their own credentials.
I don't know a clear distinction between "accomplish and explain" and "write answers" for academic study.
Employers are using other methods, such as personality tests, coding interviews, work-for-free exercises, requiring "experience" for entry level jobs, and so forth.
Employers could abolish that system overnight by simply eliminating the degree requirement. They could reduce their labor costs, because a person with no college debt might be willing to start out at a lower salary and be more loyal to their initial employer.