Personally, I've hired many great candidates, and got several great jobs, via whiteboard interviews. It's not perfect but it's far superior to takehomes, which are completely one-sided, very hard to get right (by the recruiting company), and often are boring.
Whiteboard interviews and (even better) pair-programming with an interviewer are reciprocal and allow me as a candidate to learn about the company rather than just do some work for them for free. Often the tasks are more interesting too.
In my opinion, it is the takehome tasks that are "doomed". Their premise is flawed: "we don't want to invest an hour of our engineers' time in talking you worthless candidate, so we'll instead have you spend several hours coding up a task that our engineers will never take the time to check properly, since their time is more valuable."
In my opinion, the future is platforms interviewing.io, where candidates are vetted and top candidates get the minimal investment of an hour of the company's engineer time to pair-program, which is far superior and more reliable way of screening.