Instead of popularizing tennis they are making restrictions. As an alternative they can post videos of matches/highlights on their own websites. They don't do that either. They don't even sell them.
This. Regarding popularizing of the sport, everybody should look up to the NBA. Marketing and popularizing on many ways, including bunch of various videos - highlights, analysis, interviews, funny stuff - all kinds of videos, available on the site and on yt. People also upload their own stuff on yt, including some of the full matches.
So when average kid - a future consumer or maybe a pro - searches on yt and google sport-related content, it's like at least 1000x more likely it will be attracted to football or basketball than tennis. Maybe this is one of the reasons tennis future doesn't seem so bright?
It's definitely the reason why NBA's popularity has grown hugely, from minor local to global.