If there are no takers, then the task should not be done, yes. What a lot if people seem to imply is that these jobs should not be advertised in the first place, which I disagree with.
Unless they people causing them waste incur costs greater then they benefits, it won't change. Hiring has gone digital, reducing costs, so of course garbage job postings have increased.
That said, a lot of 'jobs' are simply H1B fodder or resume bait etc.