Probably the most substantial difference is iteration. A footballer gets many games per year with many moments per game to potentially shine or fail publicly, with stats that can be evaluated year after year. Your success as a teacher can somewhat be evaluated via testing, but that seldom tracks something close to what you're really supposed to be doing: making a difference in your kids' lives. At best that's an evaluation that has to be made by the now-grown child themselves, several years after the interactions which occurred.