Enthusiastic teachers become older teacher with no enthusiasm because teachers are not paid their worth, only paid according to longevity, which is the brainchild of the union. It appears you would rather have an unenthusiastic veteran teacher keep his/her job, continuing the standard of mediocrity.
What profession are you engaged in? Do you believe that workers in your profession should get paid and promoted according to skill, dependability, etc. etc. or merely how long they've been on the job? Just because one is a veteran does not guarantee high standards.