There are events, TV stations and world championships dedicated to them.
There is big money attached to the various disciplines, whether it is skateboarding, BMX stunt riding, motorcycle riding, extreme skiing, snowboarding etc
If you are world class at what you do, you can make a living doing something you love.
Adrenaline is a powerful drug though, and can cloud your common sense.
Wayne Ewers is right, skateboarding down an open highway with oncoming traffic in conditions that are potentially variable is not smart.
It would be fine if the only person at risk was the skateboarder, but the Brynderwyns is a narrow, dangerous piece of highway. If something goes wrong, then other motorists come into play.
It wouldn't just be all downhill for the skateboarder, the likelihood of someone else being injured or killed trying to evade the skateboarder and avoid harming them is high.
Having someone die trying to save your life in a situation you have created is surely just a little too extreme, for anyone.