The answer is quite simple - we're interested in what Google thinks is valuable, not what third-party companies think is valuable.

The only metric at the moment that has a direct correlation with Google's rankings is Organic Traffic. The more traffic a site gets, the more organic keywords it ranks for on the first page.

Metrics like DR/TF are still good and useful, but only as a secondary factor, and when Traffic isn't available (like with PBNs).