Imagine the National Football League in an alternate reality. Each player's salary is based on how long he's been in the league. It's about tenure, not talent. The same scale is used for every player, no matter whether he's an All-Pro quarterback or the last man on the roster. For every year a player's been in this NFL, he gets a bump in pay. The only difference between Tom Brady and the worst player in the league is a few years of step increases. And if a player makes it through his third season, he can never be cut from the roster until he chooses to retire, except in the most extreme cases of misconduct.
Of course, a few wild-eyed reformers might suggest the whole system was broken and needed revamping to reward better results, but the players union would refuse to budge and then demonize the reform advocates: "They hate football. They hate the players. They hate the fans." The only thing that might get done would be building bigger, more expensive stadiums and installing more state-of-the-art technology. But that just wouldn't help.
If you haven't figured it out yet, the NFL in this alternate reality is the real -life American public education system. Teachers' salaries have no relation to whether teachers are actually good at their job—excellence isn't rewarded, and neither is extra effort. Pay is almost solely determined by how many years they've been teaching. That's it. After a teacher earns tenure, which is often essentially automatic, firing him or her becomes almost impossible, no matter how bad the performance might be. And if you criticize the system, you're demonized for hating teachers and not believing in our nation's children.