Sails are great, but they are incompatible with the way we load and unload ships now. Ports are designed around unobstructed access from the top. Maybe you could make it work with tankers, but people are risk averse with those. Also sail ships need a lot of crew to handle the sails.
Some shipping companies are experimenting with other ways to use wind. You can deploy kites to pull the ship, but that brings some operational challenges. The more promising idea are probably flettner rotors [1]. Those look like big spinning columns and work on the Magnus effect (how wind puts a 90 degree force on spinning objects). Their limited footprint makes them easy to integrate into existing designs, and since all they do is spin they are easy to use with the small crews of todays ships.
All of those modern ideas are mostly for reducing fuel consumption though, not replacing the engine entirely.