Nuno Rita, I wouldn't fool myself about concert going, based on my preferences. MK has attracted all ages in Greece when he came around in 2008, many of them guitarists (metal fans as well) paying tribute to the man. But I guess the recent sales were not that good and it is a solid indicator about concert goers, or so it seems. Knopfler got more fans than Dylan or Loenoard Cohen, around that time, but Depeche mode and Iron Maiden and Roger Waters sold 8-15 times the tickets. And yes the audience for these bands are about the same age, but attract a whole lot more teens and people in their early twenties.
The point was made by mr. jbaent earlier, being from Spain he shares this problem with us!