It should be obvious why this happens. Parents look for family homes once their children are born (or in anticipation of the birth of their children), and naturally parents consider the local school reputation, results and intake when they consider where they will buy or rent. Those with a choice of where to live, and therefore where to school their children, will exercise that choice.
Over time, as more (or fewer) parents want to live in an area around a school, the school’s reputation and results will rise (or fall). This is because the key driver for a school’s reputation and results is how much of an effort parents have made to get their children into the school. Of course, schools with good results are often well run places, with excellent and effective teaching. But the school’s task gets easier the more parents support the school and vice versa. Schools reputations, results and intakes evolve together.