“Dance has retreated to being just plain dance. The big companies, worldwide, are in the doldrums — what’s the last new piece that le tout New York had to go to? Who’s a star as exalted as the Margots and the Mishas? The ground has leveled: We’re reduced to the latest (exhausted) new wavelet at B.A.M., the smorgasbord at the Joyce, A.B.T.’s tired full-evening classics (except when they aren’t), and City Ballet’s 70th or 80th new piece by Peter Martins. And what about that scarily graying audience in those scarily unsold-out theaters?” Is the antidote a cheap dance festival with screaming fans?