Having been in the gang for two and a half years already made one an old hand; Hand Grenade wanted to take out Morton, but Morton wasn't new to dealing with rookies for his first two and a half years—
Why cast Hand Grenade onto this territory, a territory with many of Burger King's businesses?
It was all about letting the rookie fend for himself—if you could collect the protection money from Burger King, then you truly were badass.
This was the biggest hurdle for underlings to rise in rank: even if he was more capable than the boss, there were always a bunch of loyal henchmen...
But the resources in the boss's hands were his alone, until he became the boss, he just didn't have access to these channels, this information.
However, Lille vaguely remembered that in the game "Cyberpunk 2077," Hand Grenade had indeed risen to the top.
Maybe there is some advantage to being stupid—being brash, sometimes you really can catch them off guard.