I would be prepared to wager that more people will watch the Champions League semi tomorrow that the whole RWC combined.
The last rugby world cup final (2007) was only the 4th most watched event that year. Behind superbowl, formula 2 bahrain GP, and Champions league...
https://www.sportbusiness.com/news/163370/super-bowl-the-world-s-most-watched-live-tv-sports-event-in-2007
The 2007 Super Bowl was ranked the world�s most watched live TV sports event last year according to Initiative Sports Futures� ViewerTrack global trends report for 2007.
Initiative Sports Futures, published the report showing the top 10 live TV events for 2007, drawn from a pre-selected list of 15 events viewed worldwide and chosen for both their sporting importance and commercial value.
The report says an average live global audience of 97 million people watched the Indianapolis Colts defeat the Chicago Bears.
Following the NFL Super Bowl in second place was Formula One�s Brazilian Grand Prix, followed by the UEFA Champions League Final. The IRB World Cup Final came in fourth place, followed by World Athletics Championships; MLB World Series; IIHF World Men�s Handball Championship Final; US Masters (Final Day); Wimbledon, and the ICC World Twenty20 Championship Final.