Boston Ballet’s Nutcracker has been ousted from its annual nest in the Wang Center (replaced by a high-stepping Rockettes show). It is, the ballet company says, a blow against a tradition that has entertained Bostonians for generations. Maybe not – the Nutcracker tradition didn’t take root seriously around the US until the 1950s, and is only 35 years old in Boston. And while it’s a cash cow for ballet companies, there are certainly many who would not be unhappy artistically if the whole thing went away…