You can put a helluva lot of sails on a ship. The Preußen (1902) had 73,200 sqft of sail area on a ship 482 ft long. The Very Large Container (VLC) ships that hold 200,000 tons are over 1,300 ft long. And wind is a very, very strong force (it damaged these mechanical sails!). You could definitely make a VLC ship that could be powered by sails, in theory.

But wind's biggest downside, besides it sometimes being too strong, is it can completely stop. That and the complexity of sails, and its potential for failure, would probably not make it economically viable. Even if it was technically cheaper, the inconsistency and potentially poor performance would lead customers to continue chartering motorized vessels. There's a reason everyone switched from sail to steam.