1) What gets youngsters involved is not organization by a governing body (local, national, international). It's seeing something they want to become. They see the "stars" (whether local in the club, or national/international on broadcast) and want to become a star one day. Then they will seek out how to do that. If MR never had a Jr event (which they of course do), they would still be growing pool for the next generation, by creating interest for the next generation.
Just an example outside of pool. PDC is Professional Darts Corporation, Matchroom-operated. There is an aspiring darts player who plays many pro events, sometimes beating the very top players. He is a plumber. Last week he arrived at one of the biggest events of the year right from his morning shift, after doing his plumbing duties.
A 2018 world champion worked as an electrician. Out of the blue he made it to the finals and defeated Phil Taylor, who is easily "Efren Reyes of darts" in his prime, a legendary figure. That electrician decided to turn full-time pro then.
This is how the world of pro pool will look like. We are going to have plumbers and electricians competing at the pool table. Probably one or two of several hundred will turn full-time pool pros...