I guess too labor intensive, and probably problems scaling up to the size of current ships. Consider the last generation of sailing cargo ships before steam took over (https://en.wikipedia.org/wiki/Windjammer ), those were around 2000-5000 GRT, compared to a big container ship today at something like 170000 GRT. The tonnage difference is rather massive.
Also, if you look at pictures of windjammers, masts, rigging etc., would get in the way of cargo handling. Less so on a tanker compared to, say, a container ship, of course.
Also, if you look at pictures of windjammers, masts, rigging etc., would get in the way of cargo handling. Less so on a tanker compared to, say, a container ship, of course.