Philip Moriarty has published an Open Letter "We reject the absurd QS/THE World University Rankings", which has so far been signed by 107 academics. While I agree with the sentiment, this list of distinguished academics have missed the point of university rankings: they aren't about scientifically measuring the scholarly & educational worth of institutions, they are a marketing tool. As a marketing tool, and a publishing business, rankings have been very successful. However flawed, the rankings are a response to a real need from students, to provide advice on the quality of institutions.
When I wanted to study internationally, I turned to ranking systems to check the university I had selected was okay. I didn't care exactly where it rated, but more so it was actually a real university, not a scam. For this I used the Webometrics Ranking of World Universities, as it lists many more than the commercial ranking schemes, and is more open.
If academics want to do away with the current silly ranking systems, they have to come up with something better, which measures what they think should be measured. They then need a marketing strategy to have it adopted, and a business model to sustain it.