Why theatre is still all white on the night

The Independent: "When was the last time you were at the theatre and you sat next to someone who didn't happen to be white? Schemes such as tickets for a fiver and free tickets may well have attracted young professionals to theatre but its done little to reach out to ethnically diverse audiences. When it comes to theatre, it appears that British-Asians just aren't interested. So why do so few Asians visit the theatre?