I genuinely don't know if I'm BU. I'm in a choir and we have regular concerts. We're an amateur choir but pretty good and tickets are cheap - all proceeds go to charity. Locations are easy to get to - nothing miles away or with difficult parking etc.
I've been in the choir four years and have done about 10 concerts. DH comes every time (even though I've said he doesn't have to - he is the kindest person in the entire world) and my kids come when they can.
My local friends know when the concerts are on but they haven't come to a single one. If the tables were turned I'd be dying to see them performing - I wouldn't go to every concert but I'd go to one at least. AIBU to be annoyed they haven't made the effort? To be clear these are people I'm close to, not acquaintances.