Didn't want to ever call a teacher sir again when I moved from Scotland, so many didn't deserve it and it was the correct term, at a bloody government school. So glad it wasn't the done thing here. Then had a great male teacher that I couldn't help but refer to as Sir, he definitely deserved it. Changed my tack since then.
I like Sir as part of Rugby vernacular. Hope it stays. But as with most things, it should be culturally driven by role models, not mandated by some archaic code of conduct. If it dies a natural death, all well and good.