Baseball TV ratings
The main difference between the World Series and the NBA Finals or Stanley Cup Finals in 2020 was the NBA Finals and Stanley Cup Finals weren't played on time, they were played at a different time of year than usual.
Coronavirus isnt an excuse for bad Baseball TV ratings, since more people than usual are at home and out of work, you would think more people than usual would be watching TV, not less. People knew the World Series was going on by the time they found out the NBA Finals and Stanley Cup Finals still went on.