Indeed, good article, I have some time for Branson, he's not perfect but he does seem to have a relatively level head on his shoulders...when he's not trying to fly around the world in a hot air balloon.
But yes, trying to freeze the barons and sellers out of the market by undercutting them and removing the criminal element means that sellers have to either legitimise themselves and play by the rules or lose trade to more secure sources.
It's not perfect, and price and availability would play a big role in how successful any attempt would be, but it would probably be a step in the right direction.
Same goes for prostitution if I'm honest, criminalising it just makes things worse, because it's not going to go away, it is the oldest profession after all.