Even though the community loves to talk about one tricks, I've seen a lot of "one tricks" that have 4 to 5 hours on different heroes but 30+ hours on a singular hero.

You are bound to have hours on other heroes if you one trick. Especially if you one trick popular heroes.

There are 2 mercy players on average every game. You really think you won't be too late to lock in mercy before the other mercy player in every game?

What if its genji? tons of genji 1 tricks. You are obviously going to be in games where there is another genji 1 trick and he might pick genji before you thus forcing you to have time on other heroes.

A couple hours on other heroes doesn't mean you aren't a 1 trick. If you only play other heroes when your hero is locked away. You are basically a 1 trick who was too slow to lock in the hero you wanted to play.