For today, a few questions on the blues

Can someone explain to me why as someone deep into the blues I would want to see Marshall Tucker headline a Blues Festival? There are plenty of rock festivals that Marshall Tucker plays at. How many of those go out of their way to feature some real deal blues? 

Today I gave another listen to the CD by Austin Young & No Difference. Another supposed blue prodigy. Wouldn't it be nice if he showed signs of channeling Eddie Taylor and Matt Murphy, as opposed to SRV. If I call this a rock record, can anyone explain why it isn't? I did not like this recording but that is immaterial to the point I am asking about,

Related to these is another question. How is music, that can readily be classified as rock, keeping the blues alive? Here are someone else's astute thoughts on this.  http://bluesjunctionproductions.com/an_editorial_by_david_mac

Here is a terrific quote from David's editorial:

"When I ask someone in any town in America who is the best up and coming blues musician is their community, if it is not some kid whose parents think he is going to be the next Stevie Ray Vaughan, it is this, “incredible female vocalist who can really belt.” These “singers,” by the way, come in all races, ages, creeds and colors. Typically their interpretation of blues sounds like Janis Joplin trying to pass a pine cone while riding on a roller coaster at high altitude." (Italics added).

This brings me to the Willie Dixon quote, "The Blues is the roots, everything else is the fruits." While perhaps true a few decades ago, on what basis can anyone claim this is true of the blues today?