Genuine Question… How do some people not get bored playing 1-3 characters?

This isn’t an insult or a slight to those who enjoy the hell out of one particular character but I simply am curious to know. Given how time consuming it is to raise hero level, how do some people out here have level 500+ on some heroes while other aren’t past 20? Does the game not get repetitive or boring just playing a single/small subset of heroes? Me personally, I have my favorite heroes in the game that I play more often than the others (Ashe, Mauga, Ramattra) but as much as I love those heroes, I cannot bare playing them and only them. I feel for a game that has 50 heroes, limiting yourself to just 1-3 is such a disservice to yourself given the amount of variety that the game has to offer. But that’s just my opinion, what is yours?