Honestly even with youtube and social media there is a huge potential for people to fly under the radar. Just think about all the excellent senior players out there that have no desire to use a computer. Granted they may not be interested in going pro but they should be allowed to participate in local leagues or tournaments. It is possible for anyone to go out and buy a table of their own and practice till they become a great player. In fact with youtube and the internet they could have all the training available to anyone out there right in their own home. I am a firm believer that there are probably hundreds if not thousands of pro level players not competing or rated in any systems.
I don't see the problem. New players will always be coming in to the system, and if they want to play league or handicap tournaments, they'll have to be given a temporary rating until they're established. They're not going to be kept out, that would mean no new person ever gets in. If you're talking pro-level tournaments like Turning Stone or Derby City, they don't play with handicaps anyway.