Please don't perpetuate the misuse of this phrase, which is so often used to denigrate those with expertise and desire trying so hard to pass them on. Consider

Please don't perpetuate the misuse of this phrase, which is so often used to denigrate those with expertise and desire trying so hard to pass them on. Consider the possibility, say, in a guild context: those who can, do. They work for the guild, and do whatever the guild does. Those who can't, from age, infirmity, injury: they teach, passing on knowledge and wisdom.