Zane Grey’s writing is corny, clunky, and amateurish.
“Out of date” is a polite way to describe his language and attitudes, which are casually racist. His characters, at best barely better than cartoonish, adhere to age-old sexist stereotypes.
The historic popularity of Zane Grey’s work can only be understood as his readers’ recognition of their own values in the “Old West” mythology of white settlers, ranchers, rustlers, and gunmen as the heroes of a white-supremacist melodrama.
The anti-Mormon screed in Riders of the Purple Sage, too, would have appealed to most of his readers.
Tony Hillerman’s detective novels, set in the same region a century later and featuring Navaho policemen Joe Leaphorn and Jim Chee, are much better on all counts.