I don't think it's a fad, but take the Giants for example. They go as Saquon goes pretty much. If Daniel Jones continues to improve, they'll be in great shape.
The Titans could have worked had they not hitched their wagon to Tannehill. Same with the Raiders, although they had to give Carr his shot. The Bengals have Mixon.
Given the choice, this is how I would build a team.
For the record, I really like the pairing of Cook and Harris, just hope they're utilized properly. We now have a Kamara/Ingram type of punch.