Your job in any political office is not to leave everything as-is and to cement yourself into that position, but to make marginal improvements, even if doing so costs you the next elections or inconveniences people (hopefully only temporarily).

Most of those marginal improvements can only be seen as something positive in retrospective, not while they're being made. While they're being made, they'll always be unpopular, as the voter base is usually not keen on defending the people that are currently in charge. That doesn't mean they won't show up in the next elections, just that they are quieter in the meantime.

in the ideal world maybe - but we don't live in the ideal world: most are trying to get re-elected, or elected to a higher office now that they have experience.

and even in the ideal world a great leader can do more in the next term if they get relected.