The biggest youtube channels are overwhelmingly related to gaming, and e-sports are a big thing in Asia and growing quickly in North America and Europe.I agree that gaming can/will take over kids participation numbers but is isnt much of a spectator thing so I cant see it swallowing the whole sports world in terms of TV etc. People mostly grow out of gaming right (not everyone but most people).
Also, what makes you think basketball might be the sport to take over?
I recall reading that Australia has the largest NBA season pass holders outside of USA. Also, every year I've noticed growing interest in the NBA playoffs, more NBA jerseys on the streets, NBA players more recognisable etc. The NBL won't be a threat but the NBA is certainly looking at growing their global footprint (and the most likely to be successful out of all the American sports). NBA is bigger than football in China which is quite amazing.