Unfortunately our thinking about how we award "exclusive rights" has hardly ever taken development and expansion of the game into account.
But you're right, how do people who haven't seen our game get a chance to see it easily and freely and develop an interest in it (and with it a longer-term contribution to the usual channels of adding value to broadcast rights or ticket and merchandise revenue)?
When the NRL first awarded their online/web rights to Telstra Bigpond they originally were going to restrict their NRL video gallery just to Bigpond customers, using the footage as a product to enhance people into Bigpond plans and in doing so restricting footage to Australia. I had to write numerous emails to point out that such a move would be shooting themselves and the game in the foot, and thankfully to date they haven't got the know-how to put that plan into action or they have sensibly abandoned it.
This you tube thing is just the same mentality - treating the game as a product that exists only to earn other people profits, instead of as a sport where the participants and fans are valued as well. Modern life is rubbish...