Correct. Never responding after an application? Par for the course. But asking someone to complete a coding challenge or even an interview and then ghosting is downright unprofessional and should be unacceptable.

Totally agree. From what we can see in this thread, when a recruiter / hiring manager / HR department makes it a regular practice to ghost interviewed candidates, it has a significant effect on the company's reputation - that they lack common decency and respect. It does not seem worth it for whatever time/effort they might have saved by such behavior. To put it another way, it seems it'd be worth spending time and effort to improve the process and experience, to improve such a reputation.