A real estate agent or a hiring manager can still walk away from a really bad property, candidate, etc. A teacher can't walk away from a really bad kid (or really bad parents!) without leaving the profession entirely.
While they can have input, the goals of the administration and district don't always aline with the goals of the teachers. Teachers want good outcomes for their students. Administration wants to avoid issues that negatively impact budgets, like getting sued by parents.
They do every single day