"They are probably too old to learn manners now and we will soon forget them"   

Most unlikely (well on the 2nd count anyway!) As I'm more than twice their age, I'm pretty sure most of them will still be doing this long after I'm gone...and if they're as good as this now......!?!
I'm not saying they are the ONLY young musicians-far from it, but they act as a magnet to other quality musicians. It's often irritating as 1/2 the space is filled with people JUST listening so you can't get in to play....

Yeah Houston....you young upstart... How can you speak with any authority when you've only been going to festivals for your whole life.
Tut tut for wasting time in your previous incarnation!!!